No AC

[Trstno1]

K-

The AC has never worked on my car since I purchased it. Testing the 12v. Lead to the compressor I get nothing. If I give the wire 12v my compressor and fans kick on and my air is almost immediately much colder. What do I check next? The low pressure switch? Is that the one on the condenser? If I short the switch and the compressor and fans come on I just have low refrigerant right? It looks as though the system is still r12 so I imagine it would be a large expense swapping to R134? I read somewhere that r12 is now illegal in most states. Why is this?

[Jonathan]

I would not suggest forcing 12v onto the compressor to actually get it to run. If indeed it is low on refrigerant, running the compressor this way will likely lead to damaging the unit.

To test whether your system is not coming on due to a low pressure problem, jumper the low pressure switch up at the front right wheel well and listen for the compressor clutch to "clack" in. Do this without the engine running, i.e. ignition key turned to accessories only. If the clutch clacks in while the low pressure switch is jumpered, then it is one of two things:

1.) your refrigerant level is low (likely)
2.) the low pressure switch itself is bad (less likely)

If you do the test and find the clutch clacks in, you then should be measuring the refrigerant pressure with gauges hooked up to the proper ports. Or measure the pressures right away.

Again, I recommend not forcing the system to run with low refrigerant.

As for getting it topped up with R12 in the US, someone else can tell you about that. I think it got banned because it was bad for the ozone layer. Converting to R134 or whatever could be expensive, yes. You could also add a can or two of the R12 equivalent stuff and see how it goes.

[Trstno1]

I would not suggest forcing 12v onto the compressor to actually get it to run. If indeed it is low on refrigerant, running the compressor this way will likely lead to damaging the unit.

To test whether your system is not coming on due to a low pressure problem, jumper the low pressure switch up at the front right wheel well and listen for the compressor clutch to "clack" in. Do this without the engine running, i.e. ignition key turned to accessories only. If the clutch clacks in while the low pressure switch is jumpered, then it is one of two things:

1.) your refrigerant level is low (likely)
2.) the low pressure switch itself is bad (less likely)

If you do the test and find the clutch clacks in, you then should be measuring the refrigerant pressure with gauges hooked up to the proper ports. Or measure the pressures right away.

Again, I recommend not forcing the system to run with low refrigerant.

As for getting it topped up with R12 in the US, someone else can tell you about that. I think it got banned because it was bad for the ozone layer. Converting to R134 or whatever could be expensive, yes. You could also add a can or two of the R12 equivalent stuff and see how it goes.

Thanks for the info. I'll check the low pressure switch next. Btw, What is the r12 equivalent stuff? Also, I noticed in the auto parts store a r12 to 134a adaptor kit. I'm assuming it's not as simple as just putting the conversion nipples on and filling with r134 right?

[hmcelraft]

Did you check fuse #10?

[cdrusn]

I've converted several cars including my Porsche 928 and my Delorean without problems. Buy the kit or just buy the low (suction) side conversion nipple that they keep in a box behind the counter. Screw it directly over the R12 nipple. Get the can of R134 Freon that also has oil in it (usually comes with a short length of hose). Put it in and see if the compressor clutch begins to grab and spin. Go to Harbor freight and buy the $49 a/c gauge set. Hook up the low pressure (blue) connection, get a regular can of R134 and the needle tapping fitting and put the can in until you reach about 35 psi. Worked for me. R12 and R134 will work together but you need the compressor oil to be full. I just changed my a/c hoses so had to drain the entire system and change out the dryer but it is ice cold. :race:

[mr_maxime]

I had DMCMW recharge mine with Red Tek R12a. It's cheaper than R12 and really cold.

[DMC5180]

Thanks for the info. I'll check the low pressure switch next. Btw, What is the r12 equivalent stuff?

R12 equivalent aka Freeze 12 if you look at the chemical make up it is a 25/75 blend of R12/134a.




Also, I noticed in the auto parts store a r12 to 134a adaptor kit. I'm assuming it's not as simple as just putting the conversion nipples on and filling with r134 right?

Back in mid to late 90's when conversions were just beginning to be common place. The conversion kits were supposed to be drop in replacements. I had a couple late 80's and early 90's daily drivers converted and never had an issue for the duration I continued using the cars. This was not the case for the Delorean though.

With original A/C lines now 33-35 years old the likely hood of doing a successful drop in 134a conversion that holds pressure for the driving season is getting slim. Component age is working against you.

At bare minimum doing a 134a conversion, requires dumping the Mineral oil out of the compressor and replacing the accumulator. It is recommended you flush the entire system for best results. You should replace the orifice tube.

Both PAG and Ester oils will tolerate blending with the small amounts of mineral oil without any serious adverse affects. This assumes most of the mineral oil was drained from the compressor and any oil in the accumulator aka reciever/dryer, is gone with it's replacement.

To do a proper conversion with the best chance of long term success requires replacing all the hoses with 134a Barrier type hose and a compressor in addition to the accumulator. This assumes the condenser and evaporator don't have any corrosion leaks.

[DMC5180]

I did some reading on the Red Tek 12a mentioned above. This looks like it will be the new normal in A/C refrigerants. The Delorean would only require about 12 oz for a full charge. However it does say it is NOT compatible with butyl rubber hoses. I'm not sure what the OE hoses are in the D. It also warns NOT to charge a system with a "0" atmosphere Hard vacuum on it. This would imply you release the vacuum after a system evacuation and fill at static atmosphere.

[Trstno1]

Did you check fuse #10?

Fuse 10 is good. Next test is jumpering the low pressure switch....

[Trstno1]

[QUOTE=cdrusn;192948]I've converted several cars including my Porsche 928 and my Delorean without problems. Buy the kit or just buy the low (suction) side conversion nipple that they keep in a box behind the counter. Screw it directly over the R12 nipple. Get the can of R134 Freon that also has oil in it (usually comes with a short length of hose). Put it in and see if the compressor clutch begins to grab and spin. Go to Harbor freight and buy the $49 a/c gauge set. Hook up the low pressure (blue) connection, get a regular can of R134 and the needle tapping fitting and put the can in until you reach about 35 psi. Worked for me. R12 and R134 will work together but you need the compressor oil to be full. I just changed my a/c hoses so had to drain the entire system and change out the dryer but it is ice cold. :race

Wow! I might have to see if there is a you tube video on this.....

[Trstno1]

R12 equivalent aka Freeze 12 if you look at the chemical make up it is a 25/75 blend of R12/134a.





Back in mid to late 90's when conversions were just beginning to be common place. The conversion kits were supposed to be drop in replacements. I had a couple late 80's and early 90's daily drivers converted and never had an issue for the duration I continued using the cars. This was not the case for the Delorean though.

With original A/C lines now 33-35 years old the likely hood of doing a successful drop in 134a conversion that holds pressure for the driving season is getting slim. Component age is working against you.

At bare minimum doing a 134a conversion, requires dumping the Mineral oil out of the compressor and replacing the accumulator. It is recommended you flush the entire system for best results. You should replace the orifice tube.

Both PAG and Ester oils will tolerate blending with the small amounts of mineral oil without any serious adverse affects. This assumes most of the mineral oil was drained from the compressor and any oil in the accumulator aka reciever/dryer, is gone with it's replacement.

To do a proper conversion with the best chance of long term success requires replacing all the hoses with 134a Barrier type hose and a compressor in addition to the accumulator. This assumes the condenser and evaporator don't have any corrosion leaks.

Is the accumulator the cylinder behind the passenger tire? I like working on my car but holy @%#! this seems a bit involved...

[Bitsyncmaster]

It's my guess none of the replacements can contain any R12. Why would it be legal to sell anything with R12? All of the "R12a", "R22a", etc types I've seen are really propane. I do think the new normal retro fits will use propane since it seems to work very good for refrigerant even though it is flammable.

By the way, I just saw cans of R134a in Walmart the other day for $4.88 a can. I'm guessing R134a will not be available for sale pretty soon.

[DMC5180]

Is the accumulator the cylinder behind the passenger tire? I like working on my car but holy @%#! this seems a bit involved...

Yes


Dennis

[DMC5180]

It's my guess none of the replacements can contain any R12. Why would it be legal to sell anything with R12? All of the "R12a", "R22a", etc types I've seen are really propane. I do think the new normal retro fits will use propane since it seems to work very good for refrigerant even though it is flammable.

By the way, I just saw cans of R134a in Walmart the other day for $4.88 a can. I'm guessing R134a will not be available for sale pretty soon.

Everything you want to know about Red Tek 12A http://www.redtek.com/win_12a_prod.html More detailed info can be found via the (green hyper-links) found on that Page.

[DMC5180]

I did some reading on the Red Tek 12a mentioned above. This looks like it will be the new normal in A/C refrigerants. The Delorean would only require about 12 oz for a full charge. However it does say it is NOT compatible with butyl rubber hoses. I'm not sure what the OE hoses are in the D. It also warns NOT to charge a system with a "0" atmosphere Hard vacuum on it. This would imply you release the vacuum after a system evacuation and fill at static atmosphere.

CORRECTION: Per the official Red Tek 12a installation guide.

Red Tek 12 a refrigerant is installed through the Low side service port and is charged as a liquid into a "0" atmosphere condition. Do Not install into system where a Hard Vacuum exists. Danger!! Do Not install in High Side Service Port.




9)
RED TEK® 12a Refrigerant is installed through the LOW SIDE SERVICE PORT AND IS CHARGED AS A LIQUID INTO A "0" ATMOSPHERIC CONDITION. DO NOT INSTALL INTO A SYSTEM WHERE A HARD VACUUM EXISTS. DANGER!! DO NOT INSTALL ON HIGH SIDE SERVICE PORT.

[Bitsyncmaster]

Everything you want to know about Red Tek 12A http://www.redtek.com/win_12a_prod.html More detailed info can be found via the (green hyper-links) found on that Page.

Although RED TEK® 12a is developed to give similar operating conditions and capacities as R12 and R134a, this product is an Alkane /Hydrocarbon and comes from the same hydrocarbon family as propane and butane. It is extremely important to know that; Commercial propane and butane must not be used in an air conditioning or refrigeration system. These fuel grade products contain high volatility and variable compositions and impurities. This will significantly reduce the reliability and performance, leading to premature failure and would result in:

Still not accepted in the USA to be used in automotive AC but other countries have approved it.

[hmcelraft]

Dave, do you really think 134a will be dropped any time soon? There are what - 200 million cars with 134a systems? And, no retro options - at least practical ones.

[Bitsyncmaster]

Dave, do you really think 134a will be dropped any time soon? There are what - 200 million cars with 134a systems? And, no retro options - at least practical ones.

I think you will get a warning before it starts getting scarce. I thought it was coming sooner since the price had started climbing a few years back.

[Trstno1]

Alright guys-

I did test the low pressure switch and by jumpering the switch the AC clutch and fans kicked on. So I guess I just have low refrigerant. Im not sure if I'm going to do the conversion to 134a quite yet prior to seeing if I can aquire either freeze 12 or R420a. Though I am curious.... How does one test the oil level in the compressor? Is there a dip stick? Will I lose any sort of pressure by removing the oil fill nut? And what do I not want to disconnect in order to not die from freon inhalation?

Also, where is the low pressure fill point on the compressor? Is it the one on the left, drivers side?

[Henrik]

It's my guess none of the replacements can contain any R12. Why would it be legal to sell anything with R12? All of the "R12a", "R22a", etc types I've seen are really propane. I do think the new normal retro fits will use propane since it seems to work very good for refrigerant even though it is flammable.

By the way, I just saw cans of R134a in Walmart the other day for $4.88 a can. I'm guessing R134a will not be available for sale pretty soon.

It is the chlorine in the refrigerants that is harmful to the environment. This was established in the Clean Air Act that dates back to the 70s. R-12 and R-22 do not contain propane.

[Henrik]

Dave, do you really think 134a will be dropped any time soon? There are what - 200 million cars with 134a systems? And, no retro options - at least practical ones.

The next refrigerant is going to be carbon dioxide at very high pressures. The AC industry and car companies have been testing it for 10+ years.

[Henrik]

BTW, R-12 is in no way illegal to use. However, it is illegal to knowingly release it to the atmosphere, to import it into the US and to manufacture it in the US.

[Henrik]

Also, the market is flooded with R-12 replacement refrigerants, and they all claim to be the next big thing. Many people will attest that they work and they cool. However, Sanden (the manufacturer of the stock Delorean AC compressor) do not recommend any other replacement refrigerant than R134a and PAG oil.

Someone in a previous post mentioned a company that recommended charging liquid refrigerant under atmospheric conditions (i.e. not under vacuum). Highly questionable. The deeper the vacuum the better. And charging liquid on the low (compressor inlet) side is typically not recommended. It can be done as long as you go slowly without causing a hydraulic lock ("slug") in the compressor.

[DMCVegas]

Although RED TEK® 12a is developed to give similar operating conditions and capacities as R12 and R134a, this product is an Alkane /Hydrocarbon and comes from the same hydrocarbon family as propane and butane. It is extremely important to know that; Commercial propane and butane must not be used in an air conditioning or refrigeration system. These fuel grade products contain high volatility and variable compositions and impurities. This will significantly reduce the reliability and performance, leading to premature failure and would result in:

Still not accepted in the USA to be used in automotive AC but other countries have approved it.

Came here to say that as well.

http://redtek.com/pdf/MSDS/MSDS_12a_302.pdf

Do yourself a favor and just stick with either R12 or R134a. Don't play around with these Hydrocarbon blends. It's not that much different than just pumping butane or propane into your A/C system.

https://www.epa.gov/snap/questions-and-answers-about-r-22a-safety

Alkanes, or HC-based refrigerants are NOT approved for use in A/C systems that were not designed specifically for them. As an aside, I don't understand why we'll swap out NCTs, door seals, fuel lines, and coolant hoses, but insist upon trying to keep the entire A/C system in place to reuse it.

R12 or R134a are your best choices when it comes to your car. Stock runs with R12, but it's really only a minor cost to upgrade to R134a, and it can give you pretty much the same performance with a much cheaper maintenance cost in the long run given that R12 is about 5x the price. And if you need to replace the compressor anyways, then you can get a much better compressor designed for R134a too. Running these HC gases are dangerous as all hell.

[Farrar]

My two cents: Don't forget in your electrical troubleshooting to make sure that your diodes have not gone bad or have a flaky connection.

[Bitsyncmaster]

BTW, R-12 is in no way illegal to use. However, it is illegal to knowingly release it to the atmosphere, to import it into the US and to manufacture it in the US.

I think it's illegal to sell it in the US to anyone not licensed to handle it.

[Henrik]

I think it's illegal to sell it in the US to anyone not licensed to handle it.

Yes, that may be true as well. While working at Sanden in the 90s all of us engineers had to get some sort of certification to handle service AC systems, more specifically refrigerants.

[DMCVegas]

Yes, that may be true as well. While working at Sanden in the 90s all of us engineers had to get some sort of certification to handle service AC systems, more specifically refrigerants.

Yup. The certificate is $20 and you can test online to get it.

https://www.epatest.com/609/

[Trstno1]

Yup. The certificate is $20 and you can test online to get it.

https://www.epatest.com/609/

Nice, thanks!

[Trstno1]

Do you guys know if the red trek 12a works with the mineral oil currently in the system? Also, is there any way to check on the level of the mineral oil in there?

[Henrik]

Alright guys-

I did test the low pressure switch and by jumpering the switch the AC clutch and fans kicked on. So I guess I just have low refrigerant. Im not sure if I'm going to do the conversion to 134a quite yet prior to seeing if I can aquire either freeze 12 or R420a. Though I am curious.... How does one test the oil level in the compressor? Is there a dip stick? Will I lose any sort of pressure by removing the oil fill nut? And what do I not want to disconnect in order to not die from freon inhalation?

Also, where is the low pressure fill point on the compressor? Is it the one on the left, drivers side?

The Sanden compressor does not have a sump. The oil that is in the compressor when you first install it will get dispersed and circulated around the AC system the very moment you first kick on the compressor, so don't expect a specific oil level in the compressor at this point. The dip stick is pretty much useless. The lubrication of the compressor comes from the oil that is carried with the refrigerant as it circulates around the AC system and enters/exits the compressor. (The ideal oil circulation ratio is 3% by weight - fyi - but none of that really matters here.) So the compressor sees a steady and continuous supply of cooled oil.

If you unscrew the oil plug on the compressor you will blow the entire refrigerant charge. Don't do it. The oil will make a mess in your engine compartment, maybe even your entire garage and you may get frost-bite from exposure to the refrigerant. Freon is not poisonous but it is odorless; the danger comes in if it displaces the air that you breath in a small confined space.

So, back to basics: Check your pressures with refrigeration gauges; look for/fix leaks; evacuate the system and fill the recommended amount. I am not going to elaborate on this part - there should be plenty of youtube videos that walk you through this. Good luck!

[Henrik]

Do you guys know if the red trek 12a works with the mineral oil currently in the system?

I am sure Red Trek will claim "yes". That tends to be the point of these aftermarket replacement refrigerants.


Also, is there any way to check on the level of the mineral oil in there?

See my previous post. Actually, if you go to sanden.com and click on their Support tab you will find everything you need to know right there.

[DMC5180]

If you plan to use the Redtek 12a. Go to their official website for installation procedures and volumetric equivalent charts for the amounts to use. I post a link to their site back on page 1 of this thread. Fwiw the amount of Redtek 12a needed is about 35% of that for R12.


Dennis

[Trstno1]

If you plan to use the Redtek 12a. Go to their official website for installation procedures and volumetric equivalent charts for the amounts to use. I post a link to their site back on page 1 of this thread. Fwiw the amount of Redtek 12a needed is about 35% of that for R12.


Dennis

So just curious.....if I decide to go with Redtek12a will I need to drain the system first or could I just fill it with the refrigerant/oil blend and see if the compressor kicks on?

I'm going to check around town, but if R12 is illegal I'm fairly confident that nobody will touch it with a 20 ft pole. So I guess that leaves me working on it. If that's the case I wouldn't mind trying a new product especially if it means that I don't have to replace anything to do so. If RedTek12a ends up shortening the life of AC components so be it. As it is, it doesn't work now....

Has anyone used this kit? It's on Amazon for $75 right now.

Oh, and just to clarify.....The low pressure fill is the one on the left (drivers side) of the compressor right? Is there currently a vacuum in the system?

[DMC5180]

So just curious.....if I decide to go with Redtek12a will I need to drain the system first or could I just fill it with the refrigerant/oil blend and see if the compressor kicks on?

I'm going to check around town, but if R12 is illegal I'm fairly confident that nobody will touch it with a 20 ft pole. So I guess that leaves me working on it. If that's the case I wouldn't mind trying a new product especially if it means that I don't have to replace anything to do so. If RedTek12a ends up shortening the life of AC components so be it. As it is, it doesn't work now....

Has anyone used this kit? It's on Amazon for $75 right now.

Oh, and just to clarify.....The low pressure fill is the one on the left (drivers side) of the compressor right? Is there currently a vacuum in the system?

The system should be empty and vacuumed. Any R12 still in the system (legally) must be recovered using a service machine. It is Illegal to knowingly dump R12. R12 is a legal product but you must be certified service shop to purchase it. It's been 22 years since it was outlawed to be in NEW automobiles. There are fewer and fewer shops dealing with R12 these days. It requires separate equipment.
I'd bet if go to your local auto parts place and ask the manager if he knows of any shops that still work with R12, he'd be able to point you in the right direction. Salvage yards are a good place for this also. They must recover all refrigerants from salvaged vehicles.

The low pressure port is identified with S (suction) on the compressor head.

[Ryan S.]

Check your local Crigs List. Sometimes you will see r12 cans for sale. Might be expensive. Like $25 per can.

[Jonathan]

I have RedTek12 in my car and have not had any problems with it. I need to put more in again though as it has leaked out enough to not satisfy the low pressure switch. The leak is pretty slow, probably at one of the seals at the compressor. At the time I liked the idea of getting it working again for $50 and not $2,000 if I had to go ahead and replace a bunch of the components. I choose not to follow the fear factor notion that this is a product any more dangerous than other aspects of your car. If it was that incredibly dangerous to the public, it would already be outlawed. Look at what lengths we go to to protect our public by printing HOT on the lid of your take out coffee cup. If this stuff was so nasty and prone to bad things happening to people, all the lawyers out there would have jumped all over it long ago.

If you do take a car into a shop that has RedTek12 or equivalent in the system, even if it is near empty like mine, have the decency to mention it to the guy beforehand. The shop will empty your system ahead of time and recapture what is already in there and if he doesn't know it has had a RedTek12 product in it and that then goes through his reclaim system, you'll have contaminated it for him. He can still work on it for you, but you'll need to make sure it is completely empty first, i.e. hook your RedTek12 gauge set up to it and let it hiss empty out in the open before taking the car to him. Or he'll let it hiss out before he starts working on it.

[hippieman9]

So I have been reading the threads on A/C on here and I have a couple questions.. First My A/C blows warm. It was converted about 4 years ago by the PO at DMC CA to Red tek. I purchased a recharge kit on Amazon for the red tek. It doesn't state that it works with R12, But I called them and they confirmed that it does. They just can't advertise it. SO
I am not A/C savvy but I can work my way around it. Looking at the system I figured that the left port (Looking at the compressor, standing at the rear of the car facing the front) is the low side. I attached my gauge and started the car with the A/C cranked. I watched the gauge go from 40psi to 20psi. Now I haven't added any freon yet. The compressor kicks on at 40psi, when the gauge reached 20 it shut off. I also noticed that the cooling fans were only running when the compressor was engaged. Is this normal? I would assume that the fans should run all the time when the A/C is on.
So with all that said, It looks like the freon has enough psi, but yet it still blows warm.

Question #2With The A/C on I have noticed driving the car that the battery light will come on once in a while for a second or two and go out. only with the A/C. I have tried other combos of stuff but this is the only time i see this light come on. With that in mind the Volt meter stays steady at 13Volts. Bad ground?? Also Where are all the grounds that need to be checked for corrosion?
Thanks!!
Ryan
Vin6668

[Ron]

So I have been reading the threads on A/C on here and I have a couple questions.. First My A/C blows warm. It was converted about 4 years ago by the PO at DMC CA to Red tek. I purchased a recharge kit on Amazon for the red tek. It doesn't state that it works with R12, But I called them and they confirmed that it does. They just can't advertise it. SO
I am not A/C savvy but I can work my way around it. Looking at the system I figured that the left port (Looking at the compressor, standing at the rear of the car facing the front) is the low side. I attached my gauge and started the car with the A/C cranked. I watched the gauge go from 40psi to 20psi. Now I haven't added any freon yet. The compressor kicks on at 40psi, when the gauge reached 20 it shut off. I also noticed that the cooling fans were only running when the compressor was engaged. Is this normal? I would assume that the fans should run all the time when the A/C is on.
So with all that said, It looks like the freon has enough psi, but yet it still blows warm.

Question #2With The A/C on I have noticed driving the car that the battery light will come on once in a while for a second or two and go out. only with the A/C. I have tried other combos of stuff but this is the only time i see this light come on. With that in mind the Volt meter stays steady at 13Volts. Bad ground?? Also Where are all the grounds that need to be checked for corrosion?
Thanks!!
Ryan
Vin6668
1. Yes. Power from the Mode Switch must go through the Low Pressure Switch before reaching the compressor.

2. When the compressor coil is engaged, the winding can induce a signal into the electrical system and cause the light to come on briefly. Adding a diode across the coil input should cure the problem...
Low RPM caused by "large" Alternator Pulley diameter, etc. can also...

GROUND LOCATION LIST (http://dmctalk.org/showthread.php?1301-Ground-Location-List) in RESOURCES

[hippieman9]

1. Yes. Power from the Mode Switch must go through the Low Pressure Switch before reaching the compressor.

2. When the compressor coil is engaged, the winding can induce a signal into the electrical system and cause the light to come on briefly. Adding a diode across the coil input should cure the problem...
Low RPM caused by "large" Alternator Pulley diameter, etc. can also...

GROUND LOCATION LIST (http://dmctalk.org/showthread.php?1301-Ground-Location-List) in RESOURCES

Well, The Battery light will come on at highway speeds. A/C on, and I have the latest DMC Alternator on the car too.

[Ron]

Well, The Battery light will come on at highway speeds. A/C on, and I have the latest DMC Alternator on the car too.Since it does it at highway speeds, it's probably not the RPM/pulley. That leaves adding the diode (good bet when running late model alternators).
OR, you could have an intermittent short/drain, probably in the AC/Cooling Fan electrical system(s). If a diode doesn't work, hook a good voltmeter up and watch the readings as close as you can for more clues...


EDIT: Should of asked before- You say the light flashes on only when the AC was on. Before/After/??? it started blowing warm air?

[DMC5180]

What mode are you running the AC, Max, Normal or Bi Level. Also, make sure the temp knob is on Max cool.

Fan cycling with the AC compressor clutch engagement is Normal.


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[hippieman9]

What mode are you running the AC, Max, Normal or Bi Level. Also, make sure the temp knob is on Max cool.

Fan cycling with the AC compressor clutch engagement is Normal.


Sent from my iPhone using Tapatalk

Yes the temp level is set to cool, and Max AC.

[hippieman9]

Since it does it at highway speeds, it's probably not the RPM/pulley. That leaves adding the diode (good bet when running late model alternators).
OR, you could have an intermittent short/drain, probably in the AC/Cooling Fan electrical system(s). If a diode doesn't work, hook a good voltmeter up and watch the readings as close as you can for more clues...


EDIT: Should of asked before- You say the light flashes on only when the AC was on. Before/After/??? it started blowing warm air?

Are you suggesting hooking volt meter up to the battery and watching the volts?

I purchased the car at the end of March in Phoenix AZ. I drove it home. While driving it home I tried the AC, Noticed that only blew warm and the Batt light would sporadically come on. Seemed as if it would come on when the compressor would engage. But not every time the compressor would engage. I was thinking it may be a dirty ground.

[Bitsyncmaster]

The diode fix is mostly to fix a flash of the battery light when the compressor switches off. I do however recommend every one install the diode on the compressor clutch because it can fix other problems with electronics.

[DMC5180]

Yes the temp level is set to cool, and Max AC.

What is the clutch cycle frequency duration in seconds ON then OFF?




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[Ron]

Are you suggesting hooking volt meter up to the battery and watching the volts?

I purchased the car at the end of March in Phoenix AZ. I drove it home. While driving it home I tried the AC, Noticed that only blew warm and the Batt light would sporadically come on. Seemed as if it would come on when the compressor would engage. But not every time the compressor would engage. I was thinking it may be a dirty ground.Yes.
This could easily be two separate (but related) problems.
If the light flashes on when the clutch engages, my guess would be something related to the sudden demand for power, by the clutch and/or fans ect. drawing too much power when first turned on, alternator/regulator problem, or bad ground(s).
If the light flashes when the clutch disengages only, like Dave and I said, a diode should fix that. And I agree, you should add the diode in any case!

You should hook up the gauges to the high side too. Unless the charge is extremely low, the low side pressure alone tells you little to nothing. (It sounds odd, but half charged or overcharged, IF it is allowed to totally cool, it will read the same pressure (eg At 70F 1oz or 3oz of R12 will show ~71 psi). It may simply be too low...

To check- Haw River shows about 80F today. Using the chart at N:09:01, with an ambient of 80F the clutch should cut OFF when the high side is at 145-190 psi and the low side is at 25-32 psi with R12 (pressures might be a little higher with 134a or other types, but it should still cool well). If the high side is too low, add refrigerant... If the low side is too low, adjust the low pressure/cycle switch...
If an alternate refrigerant gives problems here and everything else is OK, let the high side rule...
The pressures should be re/checked when the ambient temp is near the highest expected for the area the vehicle will be driven in, especially when using alternate refrigerants, to avoid excessively high pressures...

[dn010]

The diode fix is mostly to fix a flash of the battery light when the compressor switches off. I do however recommend every one install the diode on the compressor clutch because it can fix other problems with electronics.

I had to do this fix - my light would come on any time I'd switch the AC off. Funny though, this only happened after my EFI install, never prior.

Anyway, I couldn't buy a single diode- I had to order a minimum of 10 so if anyone wants me to send them one, let me know and I can drop it in the mail.

[hippieman9]

I had to do this fix - my light would come on any time I'd switch the AC off. Funny though, this only happened after my EFI install, never prior.

Anyway, I couldn't buy a single diode- I had to order a minimum of 10 so if anyone wants me to send them one, let me know and I can drop it in the mail.



So where does this Diode go? Where is it installed? Do you have a pic? Is this a tech service bulletin?

[dn010]

So where does this Diode go? Where is it installed? Do you have a pic? Is this a tech service bulletin?

The diode gets installed by the AC compressor at or near the connector. This is not a service bulletin, this is a solution Dave M found for negative electrical spike, the link to his original post is below.

http://dmctalk.org/showthread.php?12203-Electrical-noise-fix-for-AC-compressor-clutch

[Bitsyncmaster]

So where does this Diode go? Where is it installed? Do you have a pic? Is this a tech service bulletin?

I have these diodes kitted (wires soldered on and shrink tubing over them that I can sell. $10 if included with another order or $15 if shipped alone. I should update my price list to show I have them.

[hippieman9]

The diode gets installed by the AC compressor at or near the connector. This is not a service bulletin, this is a solution Dave M found for negative electrical spike, the link to his original post is below.

http://dmctalk.org/showthread.php?12203-Electrical-noise-fix-for-AC-compressor-clutch

Ah ok. Well, I do need to check all my grounds too. Just in case that may be the issue. Now that I know the fans will only kick on when the compressor is engaged or the coolent temp trips the Otterstat. I know My fans are working correctly. My fans are original, I have been looking at Delorean parts NW fan kit and I wonder if they will help with the current draw since they require less to operate. This should put less strain on the charging system and have the added benefit of Cooling the antifreeze Quicker with more air pull.

[Bitsyncmaster]

Ah ok. Well, I do need to check all my grounds too. Just in case that may be the issue. Now that I know the fans will only kick on when the compressor is engaged or the coolent temp trips the Otterstat. I know My fans are working correctly. My fans are original, I have been looking at Delorean parts NW fan kit and I wonder if they will help with the current draw since they require less to operate. This should put less strain on the charging system and have the added benefit of Cooling the antifreeze Quicker with more air pull.

I highly recommend installing one of the vendors low power fans. The OEM fans seem to draw more current then the wiring can handle as they age.

[dn010]

I highly recommend installing one of the vendors low power fans. The OEM fans seem to draw more current then the wiring can handle as they age.

+1, I have DPI's setup and you can hardly tell they're running, original fans would cause my engine to bog down a little and voltage to drop.

[hippieman9]

What is the clutch cycle frequency duration in seconds ON then OFF?




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The compressor runs for just under 2 sec and disengages for just over 3 seconds. Mode switch set to max AC and the temp is the same coming out of the vents as the ambient temp. The batt light seems to come on when the clutch disengages on the compressor, sometimes, not every time. I only have a low side gauge and it reads 40psi. When the compressor kicks on it drops to 25psi. Then it shuts off and returns to about 40 psi when the compressor will kick back on again

[DMC5180]

What is your static pressure with the engine off and cross referenced to ambient temperature.


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[hippieman9]

56288
What is your static pressure with the engine off and cross referenced to ambient temperature.


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[hippieman9]

So just curious.....if I decide to go with Redtek12a will I need to drain the system first or could I just fill it with the refrigerant/oil blend and see if the compressor kicks on?

I'm going to check around town, but if R12 is illegal I'm fairly confident that nobody will touch it with a 20 ft pole. So I guess that leaves me working on it. If that's the case I wouldn't mind trying a new product especially if it means that I don't have to replace anything to do so. If RedTek12a ends up shortening the life of AC components so be it. As it is, it doesn't work now....

Has anyone used this kit? It's on Amazon for $75 right now.

Oh, and just to clarify.....The low pressure fill is the one on the left (drivers side) of the compressor right? Is there currently a vacuum in the system?

Yes I just purchased this kit from Amazon. And yes the low pressure side is the driver side port.
I called Red Tek to confirm if this works with R12 and they stated it does. They just can't advertise it. Also My Car was converted to Red Tek about 4 years ago per the receipts from the PO.

[DMC5180]

56288

What was the ambient air temperature when you took the photo?




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[hippieman9]

What was the ambient air temperature when you took the photo?




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it was 78 degrees

[DMC5180]

it was 78 degrees

At that temperature you should have been seeing around 80 psi static. The system is probably near empty.

Here is the vapor pressure chart for Redtek 12a

http://www.redtek.com/English/product.asp?ID=47.

They reference two different pressure methods. I would have to believe bubble is the one you would use with the gauge.

I would call their tech support line for clarity and further questions.


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[hippieman9]

At that temperature you should have been seeing around 80 psi static. The system is probably near empty.

Here is the vapor pressure chart for Redtek 12a

http://www.redtek.com/English/product.asp?ID=47.

They reference two different pressure methods. I would have to believe bubble is the one you would use with the gauge.

I would call their tech support line for clarity and further questions.


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I called Red Tek and they suggested that its low as well. They said that chart is "Super technical" and couldn't explain it to me. LOL I just don't want to over charge the system. If your A/C Is working properly and charged where it should be, If you have the setting on MAX will the compressor run all the time? Or cycle? Again mine is cycling kicking the fans on and off with the operation of the compressor. The dryer or accumulator doesn't seem to get cold either.

[Bitsyncmaster]

Your almost empty on refrigerant. If you even had one drop of liquid refrigerant you would have the normal static pressure. Hence you can not determine amount of charge via static pressure reading. Since you only have a little gas in your system the pressure will read low.

[DMC5180]

Your almost empty on refrigerant. If you even had one drop of liquid refrigerant you would have the normal static pressure. Hence you can not determine amount of charge via static pressure reading. Since you only have a little gas in your system the pressure will read low.

+1


According to the Redtek weight conversion chart you will need 12 oz or two 6 oz cans. For a full charge equivalent.

“9)RED TEK[emoji768] 12a Refrigerant is installed through the LOW SIDE SERVICE PORT AND IS CHARGED AS A LIQUID INTO A "0" ATMOSPHERIC CONDITION. DO NOT INSTALL INTO A SYSTEM WHERE A HARD VACUUM EXISTS.”


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[hippieman9]

OK, Well seems as if I was just low on freon. Added some red Tek and it is blowing nice and chill. Thank you all for the assistance.

[DMC5180]

OK, Well seems as if I was just low on freon. Added some red Tek and it is blowing nice and chill. Thank you all for the assistance.

If you were that low, you have leak somewhere. You just need to see how long in lasts.


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[hippieman9]

If you were that low, you have leak somewhere. You just need to see how long in lasts.


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Maybe so, I will keep my eye on it. Its been 4 years since it was charged.

[Ron]

OK, Well seems as if I was just low on freon. Added some red Tek and it is blowing nice and chill. Thank you all for the assistance.
(Lucky dog...;-)



...
"DO NOT INSTALL INTO A SYSTEM WHERE A HARD VACUUM EXISTS."
:headscratch: ... wonder what's up with that?

[DMC5180]

:headscratch: ... wonder what's up with that?

Yeah, no idea either. But that’s what was in the installation instructions.


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[hippieman9]

[QUOTE=DMC5180;234405]Yeah, no idea either. But that’s what was in the installation instructions.


Sent from my iPhone using Tapatalk[/QUOTE56313

This is what DMCH told me.
Red-Tek 12a Fill Procedure – DeLorean
Laws for refrigerants and R12 replacements vary by state - make sure you are familiar with them.
Products –
30lb cylinder of refrigerant (for shop use)
6oz individual refrigerant cans (can be for shop use or customers can purchase on their own) Leak Stop AC Seal Repair for o-rings, rubber areas – 4oz can that contains 2oz of refrigerant Pro Seal Leak Repair for metal components (compressor, evap, condenser, metal lines)– 4oz can that contains 2oz of refrigerant
Charge amount needed for DeLorean – 11oz of refrigerant, you can get this from pure refrigerant, or a mix of refrigerant and the leak stopping cans. Just make sure the total ounces of refrigerant itself is equal to 11.
Oil - 2 ounces of R12 compatible compressor oil Dye - 1⁄2 ounce of dye
Evacuation - pull a vacuum on the system like normal in order to be sure excess moisture, etc is cleared out.
Charging - Hold the can upright rather than inverted when charging the system. Also, barely crack open the line when filling – the refrigerant is a mix of different gases that combine best when let in very slowly. If you fill quickly like normal refrigerant, it may initially blow warm and make you think that the charge is bad or underfilled. Drive the car for about 20 minutes before making the call, as some time on the road can give the gases time to mix correctly and the AC will blow cold like it should.
No components should have to be changed out or adapted for the use of Red Tek.
Temperatures seen out of the vents are around 34 degrees on the road and about 48 - 50 at idle in the shop with no air going over the condenser.
Pressures are about 40-50 on the low side and 200-225 on the high side at idle. At about 2000 RPM, they move to about 28-30 on the low side, and 275-300 on the high side.
If you overfill and try to remove excess like normal refrigerant, the gases do not exit the car equally, so what you are left with is not a good mix that will cool correctly. It is better to underfill and then add as needed than to overfill and remove the extra.

[Bitsyncmaster]

It's normal for mixed refrigerant to charge with liquid and not use gas charging. The reason is each gas in the mixture gets pulled in differently (one changes to gas before the other). Now if your using a small can and will be using the whole can I would guess charging as gas should be fine. With a 30 lb. tank you would just be charging one of the mixtures gases.

But I thought R12a was just propane.

[DMC5180]

Interesting, it says in the official Red tek instructions that you charge as a LIQUID at “0” atmosphere. Too me that means holding the can inverted.


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[Ron]

Now if your using a small can and will be using the whole can I would guess charging as gas should be fine.
That makes sense.

The docs are FUBAR, imho.
They say to evacuate the system, which leaves a hard vacuum, which is below '0'. Then they say to install at '0'...and not where a hard vacuum exists. Contradictory...

I'm still interested in knowing how they would suggest raising it from below '0', to '0', without going with a little gas first... But when they say their own conversion chart is too complicated....

Too much BS for me with it screwing up pressure/diagnostics and all later. But, if it works for you in the end...

[Trstno1]

Hey guys-

So since this post I had coverted the AC to 134a with the original compressor and hoses. Once converted, I pulled a vacuum and charged and low and behold the AC worked. However, a year later the AC doesn’t work anymore. I figured it was just a little low on coolant due to a leak and hooked up the low pressure port to a can of 134a. I pumped a little in the system and noticed my compressor kick on, but it only stayed on for about 2 seconds then cut off again. I pumped a little more coolant into the system and had the same result. With the compressor off, the low side goes up to about 45psi. With the compressor on the pressure immediately drops and the compressor cuts off at 25psi. The pressure builds, the compressor kicks on, immediately drops to 25 psi then cuts off. If I leave the mode switch on the AC position it will keep doing it constantly. Basically the compressor will kick on every couple of seconds, run for a second or two then cut off again. Obvioulsly there is an issue, what do you guys think it might be?

[DMC5180]

The 45 OFF and 25 ON is the normal pressure switch transition points. The rapid cycling means the system is still low on refrigerant. It also depends what the ambient temp is at that moment. If your pressure gauge read 45 psi static and it was 70 degrees ambient then the system is near empty. You need 134a in it. But you really should try to find the leak first. I struggled for years playing the Add can game and finally just fixed it with a system rebuild. It’s nice having reliable A/C again.


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[Ron]

+1

[Trstno1]

The 45 OFF and 25 ON is the normal pressure switch transition points. The rapid cycling means the system is still low on refrigerant. It also depends what the ambient temp is at that moment. If your pressure gauge read 45 psi static and it was 70 degrees ambient then the system is near empty. You need 134a in it. But you really should try to find the leak first. I struggled for years playing the Add can game and finally just fixed it with a system rebuild. It’s nice having reliable A/C again.


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Yeah fixing the leak will be a winter project this year. However, I am in need of AC now. When the compressor is off how much pressure should the low side have when full of refrigerant?

[DMC5180]

Yeah fixing the leak will be a winter project this year. However, I am in need of AC now. When the compressor is off how much pressure should the low side have when full of refrigerant?

Refer to this Static vapor pressure chart: [edit] my link popped up broken. So just google 134a vapor pressure chart. Select > images.

Static pressure is not an indicator of how full the system is. It only tells you that refrigerant is present. When static, the pressures observed on a Low side and high side manifold gauge set will be equal.

Without a manifold set, you are playing a bit of a guessing game. Yes you can fill with just low side adapter hose with an inline gauge. But you are guessing at how much is in the system unless you know you are at zero to start with. If at zero you will need about 2.5 12 oz cans or 1.85-.9 lbs.




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[Trstno1]

Refer to this Static vapor pressure chart: [edit] my link popped up broken. So just google 134a vapor pressure chart. Select images.

Static pressure is not an indicator of how full the system is. It only tells you that refrigerant is present. When static, the pressures observed on a Low side and high side manifold gauge set will be equal.

Without a manifold set, you are playing a bit of a guessing game. Yes you can fill with just low side adapter hose with an inline gauge. But you are guessing at how much is in the system unless you know you are at zero to start with. If at zero you will need about 2.5 12 oz cans or 1.85-.9 lbs.




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ok. sounds good. Thank you for the reply.

[Ron]

Yeah fixing the leak will be a winter project this year. However, I am in need of AC now. When the compressor is off how much pressure should the low side have when full of refrigerant?
It doesn't work that way...
As long as there is a little refrigerant in it and it is allowed to sit until it matches the ambien temp, it will have the same pressure regardless of how much is in it. E.G., at 70F it will have ~70psi with R12 or 134a. At 100F it will have 117psi for R12, 124psi for 134a, AFTER allowed to match ambient temp.

Normally, you should evacuate and recharge. But since you are looking for temporary, you can use the chart at N:09:01.
Anchorage forecast shows a high of 70F today. So, according to the chart @ 70F, you would add until the low side is 20-25psi and the high side is 100-110psi when the clutch cycles OUT for R12. WARNING: 134a pressures run higher than R12 at higher ambient temps (not linear). So you should back off to 90-100psi and wait for a HOT day to adjust it. (Don't forget/procrastinate- Too little causes poor performance -- Too much causes poor performance AND damage!)

========

Charts are in our RESOURCE SECTION HERE. (http://dmctalk.org/showthread.php?1244-Refrigerant-Temp-Pressure-Chart)

[Trstno1]

Ok. The system was low of 134a. I topped it off and ac works great now. I’ll have to track that leak down this winter. Now I notice that when at idle when the ac compressor kicks on my engine bogs down to about 550 rpm and acts like it wants to die. When the compressor is off the world is right again and I get my 750 rpm. First, shouldn’t the car compensate for the extra load of the compressor without killing idle rpm like that? 2nd - I am running Oem cooling fans and understand the extra load on the electrical system could be partially at fault. What do you think I can do in order to use the ac without worrying about the engine dying at a stop light? Is the idle control valve a potential culprit?

Thanks in advance for your opinions.

[Ron]

First, shouldn’t the car compensate for the extra load of the compressor without killing idle rpm like that?Yes.


2nd - I am running Oem cooling fans and understand the extra load on the electrical system could be partially at fault.No, the fan's load on the electrical system only causes the alternator to kick in (if it isn't already). The alternator will then add a load to the engine, but the idle speed control system compensates for it. It should settle down at 775 ± 50 RPM, quickly.


What do you think I can do in order to use the ac without worrying about the engine dying at a stop light?- Check that the idle speed microswitch is working properly.
Prop the throttle open slightly (steady) enough to disengage the microswitch. Then using a small screwdriver, listen for the RPM to change when you push/release the microswitch. If it does, make sure that the set screw is pressing the switch at idle, especially when you ease off the throttle (sticky linkage). If there is no change, check the microswitch and its wiring to the idle speed ECU with a meter (several threads on that here).

- Feel the idle control valve (or "idle speed motor") to see if it is buzzing at idle.
Wash it out thoroughly.

- If the above doesn't help, borrow an idle speed ECU and swap yours out to eliminate it as the culprit.

- Report back with what you find...


(If you need either, I happen to have an ECU and microswitch up for sale HERE (http://dmctalk.org/showthread.php?16612-Misc-Parts-For-Sale) ;-)

[Trstno1]

Yes.

No, the fan's load on the electrical system only causes the alternator to kick in (if it isn't already). The alternator will then add a load to the engine, but the idle speed control system compensates for it. It should settle down at 775 ± 50 RPM, quickly.

- Check that the idle speed microswitch is working properly.
Prop the throttle open slightly (steady) enough to disengage the microswitch. Then using a small screwdriver, listen for the RPM to change when you push/release the microswitch. If it does, make sure that the set screw is pressing the switch at idle, especially when you ease off the throttle (sticky linkage). If there is no change, check the microswitch and its wiring to the idle speed ECU with a meter (several threads on that here).

- Feel the idle control valve (or "idle speed motor") to see if it is buzzing at idle.
Wash it out thoroughly.

- If the above doesn't help, borrow an idle speed ECU and swap yours out to eliminate it as the culprit.

- Report back with what you find...


(If you need either, I happen to have an ECU and microswitch up for sale HERE (http://dmctalk.org/showthread.php?16612-Misc-Parts-For-Sale) ;-)

Ok - yes the idle speed micro switch is working. Yes the idle speed motor buzzes and closes with the ignition on. I will swap the idle ECU when I get the chance but really don’t think its the culprit. When the AC is turned on, what tells the idle ECU to raise the RPM to compensate for the AC compressor?

[Ron]

Ok - yes the idle speed micro switch is working. Yes the idle speed motor buzzes and closes with the ignition on. I will swap the idle ECU when I get the chance but really don’t think its the culprit. When the AC is turned on, what tells the idle ECU to raise the RPM to compensate for the AC compressor?It sounds like they all might be ok.
If the micro switch is closed and you turn on the AC (or load down the engine in any other way), the ECU sees the drop in RPM and tells the idle speed motor to add more air to the air/fuel mixture, causing the fuel control system to add more fuel (because it is lean), which causes the rise in RPM.

...I'm wondering if you might have a vacuum leak only when the AC is on. Maybe try plugging the vacuum feed port on the back of the air horns and then try it.