Water under the car

[Helirich]

I took my wife for a long drive today. It was nice. I noticed the new front coilovers were bottoming out fairly easy, so I jacked up the front to access the damping adjustment. Look under the car to see water pooring out at the rear of the triangle plate. It was cristal clear water and about 1/2 gallon.

I'm assuming it is melted ice from my evaporator. I guess I need more freon. My question, is there not some drain tube for that water? I didn't jack the car up for over two hours since the drive. Don't like the idea of water sitting in there. I looked at the DMC parts diagram and didn't see any drain tube. Am I missing something?

[cdrusn]

It's definitely a/c evaporator drain water. Likely your drain hose pulled up and is dumping into the closing plate area then running to the rear of the car. That happened to me so I grabbed the hose and attached another 6 inches of heater hose to it and now it drains directly below the frame onto the ground. The evaporator will put out a lot of water if it is working correctly, it's not ice as the a/c wouldn't work if it was iced up. There is a screen in the front of the evaporator that prevents ice from forming.

[Michael]

The drain is a jacked up design. It drains through the underbody via some funky elbow rubber grommet that is impossible to attach once removed for cleaning and a drain hose that isn't long enough to keep the water off the frame. I routed a new hose from the evap, through the underbody, and under the car allowing the water to hit the ground and not the frame...a novel concept only used by pretty much all other manufacturers.

[Ron]

+1 all of the above

DRAIN TUBE HERE (https://store.delorean.com/105909-a-c-drain-tube.html) NLA

[Michael]

If yours is missing, I think I used a boot from an ignition coil and a clear piece of tubing. I zip tied the bottom end to keep it from moving around too much.

[Jonathan]

Another picture here: http://dmctalk.org/showthread.php?10336-Assorted-Helpful-Technical-Photos&p=239239&viewfull=1#post239239

[Helirich]

Thanks to all. My wife didn't notice any water in the foot well. (Sandal type shoes) I will check today. If it's dry, can I assume the hose is in place and just not long enough?

Johnathan, that picture is impressive, but for the life of me, I can't see the tube. I must be blind. I assume I should look in the pax wheel well to see it on my car? Or do I need to be under the car?

My AC does freeze up still after about twenty minutes and I have to switch it off for a bit to melt the ice. On this subject, I'll query you guys on my situation.

When I got the car, my guages showed pressure in the system, but the AC pressure switch didn't work. I got a new one from DMC and it worked. (Except for freezing) After a bit (maybe two tanks of gas), it quit again. I pulled the switch and tested it and it works. If I jump the wires, the AC works, But no pressure gets to the switch. I'm guessing the shrader is clogged. I have fancy little tool that I can remove a shrader valve without releasing the freon, but in this case, the threads that hold the shrader are wrecked up. I ordered a new accumulator. (That fitting is welded in)

So right now I'm just driving with a jumper wire in place of the switch. Am I correct in thinking the only danger in driving like this is compressor failure if the freon leaks out?

[cdrusn]

You said you had pressure in the system but don't say what the pressure was. If you have the gauges what were the pressure for the low pressure side and the high pressure side with the car running and the a/c online?

[Ron]

Thanks to all. My wife didn't notice any water in the foot well. (Sandal type shoes) I will check today. If it's dry, can I assume the hose is in place and just not long enough?
Not really...


My AC does freeze up still after about twenty minutes and I have to switch it off for a bit to melt the ice. On this subject, I'll query you guys on my situation.
Low refrigerant OR restricted air flow through the evaporator can cause freeze over. If the refrigerant is low, it will expand too much when it enters the evaporator and get too cold. This causes condensation on the evaporator to freeze instead of dripping off. This in turn restricts air flow through the evaporator -- If air can't flow through the evaporator (due to this, condensation not draining, or because the evaporator/screen is dirty), heat in the air doesn't transfer to the refrigerant and get carried away to the condenser...


When I got the car, my guages showed pressure in the system, but the AC pressure switch didn't work. I got a new one from DMC and it worked. (Except for freezing) After a bit (maybe two tanks of gas), it quit again. I pulled the switch and tested it and it works. If I jump the wires, the AC works, But no pressure gets to the switch. I'm guessing the shrader is clogged. I have fancy little tool that I can remove a shrader valve without releasing the freon, but in this case, the threads that hold the shrader are wrecked up. I ordered a new accumulator. (That fitting is welded in)
You might try one of these repair tools (https://www.nashbar.com/rema-tip-top-rema-4in1-schrader-valve-repair-tool-186/p560833) first.


So right now I'm just driving with a jumper wire in place of the switch. Am I correct in thinking the only danger in driving like this is compressor failure if the freon leaks out?No, you are taking a very high risk of over-pressure, where anything in the system can blow up.
(You shouldn't rely on the high pressure switch, which many Ds didn't come with.)

[Helirich]

You said you had pressure in the system but don't say what the pressure was. If you have the gauges what were the pressure for the low pressure side and the high pressure side with the car running and the a/c online?

That wasn't really pertinent to the question, but I recall about 25 low side and 220 high side.


Not really...


Low refrigerant OR restricted air flow through the evaporator can cause freeze over. If the refrigerant is low, it will expand too much when it enters the evaporator and get too cold. This causes condensation on the evaporator to freeze instead of dripping off. This in turn restricts air flow through the evaporator -- If air can't flow through the evaporator (due to this, condensation not draining, or because the evaporator/screen is dirty), heat in the air doesn't transfer to the refrigerant and get carried away to the condenser...


You might try one of these repair tools (https://www.nashbar.com/rema-tip-top-rema-4in1-schrader-valve-repair-tool-186/p560833) first.

No, you are taking a very high risk of over-pressure, where anything in the system can blow up.
(You shouldn't rely on the high pressure switch, which many Ds didn't come with.)

I understand what's going on with the freeze up.

That tool requires recovering the freon. If/when I do that, I will replace the accumulator/dryer.

Is that pressure switch a "over pressure" also? If not, (I don't think it is) I don't see how jumping it would risk explosion. Please correct me if I'm wrong.

Also, if I "shouldn't rely on the high pressure switch , which many Ds didn't come with", what should I rely on?

[Ron]

I understand what's going on with the freeze up.
Cool.
...Before you said you were guessing. How did you determine that it is not both over charged AND had a low heat load into the evaporator?


That tool requires recovering the freon. If/when I do that, I will replace the accumulator/dryer.
My thought was that you have to dump the Freon to change the accumulator. And changing it out involves the evaporator, which does not like to be disturbed and is a PITA to replace...


Is that pressure switch a "over pressure" also? If not, (I don't think it is) I don't see how jumping it would risk explosion. Please correct me if I'm wrong.
It has an operating range, I.E., it kicks off at 25-35 psi on at 55-60 psi, depending on the ambient temp. E.G., 90F ambient => clutch off @ 25-35 psi low side, and 170-200 psi high side, according to the chart (I find the cutoff pressures much higher here).
Jumped, the compressor clutch is always on when the AC is on.
(Think 'cycle switch', not 'low pressure switch'.)


Also, if I "shouldn't rely on the high pressure switch , which many Ds didn't come with", what should I rely on?
The same as they...:evilgrin:
That the system is sound and charged correctly. And that nothing goes wrong. (seriously)

EDITS in RED

[Helirich]

Cool.
...Before you said you were guessing. How did you determine that it is not over charged AND the heat load into the evaporator is low?


My thought was that you have to dump the Freon to change the condenser and changing it out involves the evaporator, which does not like to be disturbed and is a PITA to replace...


It has an operating range, I.E., it kicks on at 25-35 psi, and off at 100-300 psi, depending on the ambient temp. E.G., 90F ambient => clutch on @ 25-35 psi, clutch off =>170-200 psi, according to the chart (I find the cutoff pressures much higher here).
Jumped, the compressor clutch is always on when the AC is on.
(Think 'cycle switch', not 'low pressure switch'.)


The same as they...:evilgrin:
That the system is sound and charged correctly. And nothing goes wrong. (seriously)

In my experince, freeze up is due to low charge or low airflow through the evaporator. (My airflow is good) I've never heard of an overcharged system freeze up. (I'm not saying your wrong) I guess I need to do some reading on that. I don't understand how overcharge would make the heat load low.

I wasn't going to change the condenser, just the accumulator to get a new shrader. (Maybe that's what you ment) I didn't plan on disturbing the evaporator. Isn't it all hoses? Why would that disturb it?

I did not realize that was a high/low switch. DMC calls it a "low pressure switch". In any case, it's very unlikely to have the low side get that high. Let's face it, a lot could explode before that gets high. (Like a clogged orface explode the condenser)

Anyways, thanks for the info.

[Jason]

Here is kind of where the drain tube should be, though I think on most cars it may be slightly more rearward and hidden by body tub. This is looking between the rearward side of the front passenger wheel and the fender.
6633766338

[Ron]

In my experince, freeze up is due to low charge or low airflow through the evaporator. (My airflow is good) I've never heard of an overcharged system freeze up. (I'm not saying your wrong) I guess I need to do some reading on that. I don't understand how overcharge would make the heat load low.
It won't unless the heat load to the evaporator is low also...


I wasn't going to change the condenser, just the accumulator to get a new shrader. (Maybe that's what you ment) I didn't plan on disturbing the evaporator. Isn't it all hoses? Why would that disturb it?No, only one hose, from compressor. The other port connects directly to the evaporator. (You would be dealing with thin, weathered aluminum and a crowfoot...)


I did not realize that was a high/low switch. DMC calls it a "low pressure switch".
And they call the Bonnet Seal a Hood Seal....:smile:


In any case, it's very unlikely to have the low side get that high. Let's face it, a lot could explode before that gets high. (Like a clogged orface explode the condenser)
I can't count the times I've found that switch being bypassed or shorted internally being the sole cause of a blowout.
If it has at least a full charge and you run it in an ambient temp of 90F+ with it jumped, you will change your mind.


Anyways, thanks for the info.
NP!

[Jonathan]

Jonathan, that picture is impressive, but for the life of me, I can't see the tube. I must be blind. I assume I should look in the pax wheel well to see it on my car? Or do I need to be under the car?

6634266341

[cdrusn]

There is only one connection between the evaporator and the condensor and that is a single hose going through the accumulator. Removing the freon is solely done at the compressor. At this point, with so many people who don't know what they are talking about telling you what to do, I recommend you go to an a/c shop and have them give you their professional opinion. Then take their advice to fix it your self. For sure, if your low pressure is 25, you need a can of freon to bring it up to 40.

[Ron]

There is only one connection between the evaporator and the condensor and that is a single hose going through the accumulator. Removing the freon is solely done at the compressor. At this point, with so many people who don't know what they are talking about telling you what to do, I recommend you go to an a/c shop and have them give you their professional opinion. Then take their advice to fix it your self. For sure, if your low pressure is 25, you need a can of freon to bring it up to 40.
LMAO!
I had a brain fart and meant to say "...change the evaporator". The thing I had just quoted about and suggested he might use the tool on to fix its "wrecked up" schrader valve threads with...
I thought we were together because he said, "I wasn't going to change the condenser, just the accumulator to get a new shrader. (Maybe that's what you meant) I didn't plan on disturbing the evaporator. Isn't it all hoses?" I assumed "it" referred to the previous noun, evaporator. Then again with, "Why would that disturb it?", because the evaporator is what I warned about being disturbed...
In other words, give me a freaking break!

I take full credit for the confusion, Sorry Helirich!
But in the same spirit:
No, there are two connections between the evaporator and the condenser, one at each end of the hose connecting the two.
The manual disagrees with, "For sure, if your low pressure is 25, you need a can of freon to bring it up to 40."
66353

It's spelled, "condenser".
It's spelled, "Freon".

:smile: Have a nice day!

[Bitsyncmaster]

I've found your low pressure does not change due to the amount of refrigerant charge. The low pressure PSI value is set by the low pressure switch value. Now a low high pressure value does indicate a low charge of refrigerant unless your compressor is working poorly. Now a high value on the high pressure does not necessarily indicate over charge. The air flow over the condenser could be low causing high pressure.

I've never seen a "low pressure" switch that also cuts off for high pressure. Normally the separate high pressure switch is never actuated it is there in case your cooling fans fail. There should also be a blow off valve that will vent the charge and save your system from damage.

Running R134a does run a higher high pressure value in our system designed for R12.

[DMC-Ron]

I've never seen a "low pressure" switch that also cuts off for high pressure. Normally the separate high pressure switch is never actuated it is there in case your cooling fans fail. There should also be a blow off valve that will vent the charge and save your system from damage.


Agreed. I've never seen a combo low/high pressure switch. Our systems have the low pressure switch. I've heard some owners add a high pressure switch but it's likely unnecessary. In order for the compressor to generate a high pressure it must pull the suction down to a low pressure. The low pressure switch would cut out before the high side became excessive. The exception would be if there was way too much refrigerant in the system. An overcharged system would elevate the suction pressure and prevent the low pressure switch from providing the high side protection.

Ron

[David T]

The Delorean has an unusual design to keep the evap coil from freezing. The pressure switch is set so that the compressor will cycle on and off allowing the evap coil to clear any ice. It also allows the radiator fans to stop so they don't run continuously. If you don;t adjust the system to cycle the evap coil freezes up and you overload the electrical system. You can make sure the drain is clear by taking the fan motor out.

[MrChocky]

To add to the confusion, because I don't think it's been 100% spelled out in this thread, it's not uncommon for the drain hose to get caught up around the frame for whatever reason. This happened on mine, and
the passenger side was filling with water. If you can't see it from underneath, it's worth looking in the access panel under the spare. I also ran picture wire (which has endless repair uses on a DeLorean) up
mine to clear and potentially clogging, at least to the elbow.

[Helirich]

A lot of info to take in. I'm not good at the quoting function. So first you guys that posted pics, now I see the tube. (At least in the pic, haven't looked on the car yet)

Ron, I'm having trouble with that chart. It has a column for AC discharge. I've not seen that term before. Would that be at the shrader on the accumulator? Is that where you guys take your readings? I took my readings at the compressor and it was only a 70 degree day. I wanted to wait till it was 90 out before adding freon.

It might not seem like it, but I am actually very experienced in refrigeration, but not auto AC. My wife and I owned a restaurant/bar and there a ton of refrigeration stuff in that business, so I took a course. I own all the tools. This is my first R12 system.

When I was working on the AC, it did seem to cycle a lot. I worried that it might ware out the clutch. But again, I didn't want to do to much till it was 90 out.

I've got some other pressing projects right now, so I must park the car for a couple days. I'll be back on it shortly.

[MrChocky]

When I was working on the AC, it did seem to cycle a lot. I worried that it might ware out the clutch. But again, I didn't want to do to much till it was 90 out.


Mine certainly cycles a lot; I understand this is common. It took me nearly a year to figure out the ~30 second clicking from the engine bay was in
fact the clutch. As an aside, Dave McKeen's fan relay helps avoid the fans cycling quite as much with the A/C.

[Ron]

+1 Bitsy, DMC-Ron, MrChocky


The Delorean has an unusual design to keep the evap coil from freezing. The pressure switch is set so that the compressor will cycle on and off allowing the evap coil to clear any ice. It also allows the radiator fans to stop so they don't run continuously. If you don;t adjust the system to cycle the evap coil freezes up and you overload the electrical system. You can make sure the drain is clear by taking the fan motor out.
EXACTLY!


Ron, I'm having trouble with that chart. It has a column for AC discharge. I've not seen that term before. Would that be at the shrader on the accumulator? Is that where you guys take your readings? I took my readings at the compressor and it was only a 70 degree day. I wanted to wait till it was 90 out before adding freon.
The column is for the air temp expected at the cabin duct output. (Double click the chart to enlarge it.)
Yes, take other readings at the compressor.


It might not seem like it, but I am actually very experienced in refrigeration, but not auto AC. My wife and I owned a restaurant/bar and there a ton of refrigeration stuff in that business, so I took a course. I own all the tools. This is my first R12 system.

When I was working on the AC, it did seem to cycle a lot. I worried that it might ware out the clutch. But again, I didn't want to do to much till it was 90 out.

I've got some other pressing projects right now, so I must park the car for a couple days. I'll be back on it shortly..
FWIW- I wasn't thinking what you seem to think I was thinking...I think the latter part of the discussion got off track over my (obviously poor wording/explanation). But, in my defense, I never used the term "Low/High switch" :smile:. (I edited it with changes in red, Please reread (http://dmctalk.org/showthread.php?18845-Water-under-the-car&p=264983&viewfull=1#post264983) ).

Maybe starting from scratch with an example will help clear things up:
Given:
The system is stock, sound and evacuated.
R12 refrigerant.
Ambient 70F (Box fan at radiator!)
Pressures and temps taken when clutch cycles out.

What I would expect:
When you turn the AC on, nothing happens. As you introduce the charge, both sides rise above ~60 psi (equalizing through the orifice tube), causing the cycle switch to turn the clutch on. The compressor will take from the low side and add to the high side. The low side will fall below 32-35 psi as the high side rises, causing the cycle switch to turn the compressor back off. Equalization will begin. The equalization (and the charge continuing to flow in) will bring the low side back above 60 psi, the cycle switch turns the compressor back on. This repeats until the charge is complete. .
From here (once settled down), the compressor takes from the low side, pulling it below 32-35 psi as it raises the high side to 220 psi. The cycle switch will turn the clutch off. Equalization, through the orifice tube, will bring the low side back up above 60 psi...and this repeats forever, as long as the ambient remains the same. The output at the ducts should be ~36F.
(Note, as I mentioned before, I find the high side pressures to be higher than the chart where I live, using the exact charge called for. FWIW- I believe it is ruff field data, very ruff...maybe from a Volvo :smile:
As I suspect you may already know/find interesting:
If conditions are just right, the clutch will never cycle.
Although the chart is checking data, you can use it to top off/charge the system in an "emergency". Don't quote me on that! :smile:)

[Ron]

Mine certainly cycles a lot; I understand this is common. It took me nearly a year to figure out the ~30 second clicking from the engine bay was in
fact the clutch. As an aside, Dave McKeen's fan relay helps avoid the fans cycling quite as much with the A/C.There is a little screw between the two electrical terminal for the cycle switch you can turn to help that.
Warning: This should only be done with a gauge set connected and a little goes a long way. And always double check the pressures on the hottest of days.

[David T]

There is a little screw between the two electrical terminal for the cycle switch you can turn to help that.
Warning: This should only be done with a gauge set connected and a little goes a long way. And always double check the pressures on the hottest of days.

You should only adjust that screw after filling the system with the exact amount of R-12 and making sure everything else is operating correctly. The coils are clean, both radiator fans are working, etc. DO NOT adjust that screw to compensate for an over-filled or under-filled system. If you convert to another type of refrigerant you do need to adjust the pressure switch but unless it was messed with it should not need to be adjusted for R-12. Working with R-12 is just like any other refrigerant, use the tables to confirm operation but to fill you should measure it in by weight. My system had a minor leak and I got tired of topping it off. I used a leak sealing kit and now it is perfect. The leak sealing kits today really do work. Before filling you should replace the service valve cores, drain and refill the compressor with fresh oil and pull a hard vacuum. If you have original hoses you should replace them and the accumulator (it has the dryer inside). A car's A/C can't work well unless the motor's cooling system is PERFECT. Make sure the cooling system is working as good as you can or you will have problems with the A/C too. As for the cycling, the system was made to handle it but you should check the gap on the clutch and adjust if necessary. All of this is in the Workshop Manual.

[Josh]

Agreed. I've never seen a combo low/high pressure switch. Our systems have the low pressure switch. I've heard some owners add a high pressure switch but it's likely unnecessary. In order for the compressor to generate a high pressure it must pull the suction down to a low pressure. The low pressure switch would cut out before the high side became excessive. The exception would be if there was way too much refrigerant in the system. An overcharged system would elevate the suction pressure and prevent the low pressure switch from providing the high side protection.

Ron

You cannot have a combo switch because the low pressure switch is on the low pressure side of the system (larger hose), after the orifice tube.
The high pressure side of the system (the smaller hose) is before the orifice tube, and can see pressures close to 400psi under extreme situations. If you do not have a high pressure switch and the system overpressures (can be something as simple as the radiator fans not starting with the ac) pressures can approach 500psi within a few minutes and if there is not a relief valve you can blow a hose or damage other portions of your ac system.

[Helirich]

The Delorean has an unusual design to keep the evap coil from freezing. The pressure switch is set so that the compressor will cycle on and off allowing the evap coil to clear any ice. It also allows the radiator fans to stop so they don't run continuously. If you don;t adjust the system to cycle the evap coil freezes up and you overload the electrical system. You can make sure the drain is clear by taking the fan motor out.

So, what kind of cycle times should I expect? Mchocky mentioned 30 sec. would you say that is operating correctly?



The column is for the air temp expected at the cabin duct output. (Double click the chart to enlarge it.)


I see said the blind man as he picked up his hammer and saw.


You cannot have a combo switch because the low pressure switch is on the low pressure side of the system (larger hose), after the orifice tube.
The high pressure side of the system (the smaller hose) is before the orifice tube, and can see pressures close to 400psi under extreme situations. If you do not have a high pressure switch and the system overpressures (can be something as simple as the radiator fans not starting with the ac) pressures can approach 500psi within a few minutes and if there is not a relief valve you can blow a hose or damage other portions of your ac system.

Wow, I agree with everything you just said. I guess there's hope for us yet.

[Michael]

So, what kind of cycle times should I expect? Mchocky mentioned 30 sec. would you say that is operating correctly..

Even with a correctly charged system cycle times are not etched in stone. It's about pressure. You may have a compressor that is not as strong as the next guys, or a r12 system converted to 134 woll probably not be as efficent as a newer one designed for 134. With a properly charged and functioning system, your compressor should engage around 37psi and disengage around 25(I don't have the exact numbers in front of me but I'm sure someone will correct me if I'm off so much as one degree).

Your system may cycle regularly at highway speeds but may not cycle at all at idle because the pressure may never gets low enough, especially with a retrofitted system.

It's not an exact science since so many of us have compressors not original to the r12 OE system.

Mine is a bit of a bastard child. I have my pressure switch set just a tad higher as mine is converted from r12 so I don't have to worry as much about freezing. Mine will still cycle but not as often as it did when I was on R12.

[Helirich]

I don't have the exact numbers in front of me but I'm sure someone will correct me if I'm off so much as one degree.

Got to love the Internet. Lol

[Josh]

The cycle time is dependent on the ambient temperature. The hotter it is, the compressor will cycle less as it will be engaged longer. the colder it is the compressor will engage for shorter periods of time and cycle off more than it is on.
Like Michael said pressures are everything.

[Ron]

Got to love the Internet. Lol+1! LOL

I just did a quick search on eBay for a R12 clutch cycling system switch similar to a D's, listing its range.
HERE (https://www.ebay.com/itm/311036232114?epid=12009708806&hash=item486b3441b2:g:X9AAAOxyg6BR3pa7) is the only one I could find. It fits 1980 GM - 1993 Volvo, "OFF 28psi ON 47psi".

[Ron]

The cycle time is dependent on the ambient temperature.+1

[Helirich]

+1! LOL

I just did a quick search on eBay for a R12 clutch cycling system switch similar to a D's, listing its range.
HERE (https://www.ebay.com/itm/311036232114?epid=12009708806&hash=item486b3441b2:g:X9AAAOxyg6BR3pa7) is the only one I could find. It fits 1980 GM - 1993 Volvo, "OFF 28psi ON 47psi".

On the DMC site, it says the switch is "new old stock". So I'm going to assume it's for R12. It's really strange how it worked at first and now I can't get pressure out of that shrader. Do you suppose the PO put stop leak in and it clogged the port?

It really sucks to recover the whole system to install another accumulator just to get that shrader working. I don't want to try to fix the shrader threads because I kind of have a rule. "Every time I open a system, I replace the dryer". When I worked on walkin freezers, I did triple vacuum with nitrogen sweeps in between and I still replaced the dryer.

[Ron]

On the DMC site, it says the switch is "new old stock". So I'm going to assume it's for R12. It's really strange how it worked at first and now I can't get pressure out of that shrader. Do you suppose the PO put stop leak in and it clogged the port?

It really sucks to recover the whole system to install another accumulator just to get that shrader working. I don't want to try to fix the shrader threads because I kind of have a rule. "Every time I open a system, I replace the dryer". When I worked on walkin freezers, I did triple vacuum with nitrogen sweeps in between and I still replaced the dryer.Very well could have...you know POs.
If you haven't already, maybe see that the stem is straight and moves??
{Damn, it's getting to where I spend as much time on dodging bullets and toes as the problem at hand...not necessarily aimed at you... ...LOL}

I don't do walkin, but have the same rule.

[David T]

Either the little piece that pushes on the core is missing from your hose fitting or it just isn't long enough. I use a tool that extracts the valve while my hose is connected so I don't have to vacuum and fill through the tiny opening of the valve core. The cycle time is dependent on the ambient temperature AND the RPM's of the motor. The point is, it MUST cycle or the evap coil will freeze up. I run the motor at about 1200 RPM's and use a fan in front of the car when I am charging or testing the A/C. Make sure the cabin fan is on high, temp all the way cold and mode on MAX or A/C. That gets it cycling about 10 seconds on and 10 seconds off with R-12 at about 80 degrees. Your results may vary depending on exactly how much R-12 is in your system, how clean your coils are, how much oil, etc. Just too many variables to give you an exact #.

[Bitsyncmaster]

Cycle time is also dependent on air flow over the evaporator. Turn you fan on low or turn it off and see how short the compressor cycle on time is and how long the off time is.

[MrChocky]

Even with a correctly charged system cycle times are not etched in stone. It's about pressure. You may have a compressor that is not as strong as the next guys, or a r12 system converted to 134 woll probably not be as efficent as a newer one designed for 134. With a properly charged and functioning system, your compressor should engage around 37psi and disengage around 25(I don't have the exact numbers in front of me but I'm sure someone will correct me if I'm off so much as one degree).

Your system may cycle regularly at highway speeds but may not cycle at all at idle because the pressure may never gets low enough, especially with a retrofitted system.

It's not an exact science since so many of us have compressors not original to the r12 OE system.

Mine is a bit of a bastard child. I have my pressure switch set just a tad higher as mine is converted from r12 so I don't have to worry as much about freezing. Mine will still cycle but not as often as it did when I was on R12.

And to confuse matters, I cleaned out my hamster cage, and now the system moves the air around so much better that often the A/C is too much, so I just use the fan.

[Helirich]

Cycle time is also dependent on air flow over the evaporator. Turn you fan on low or turn it off and see how short the compressor cycle on time is and how long the off time is.

Right now my cycle time is about 20 minutes. I turn it on and after twenty minutes, it freezes up and I turn it off. Lol. It will be that way till I get the shrader fixed.


And to confuse matters, I cleaned out my hamster cage, and now the system moves the air around so much better that often the A/C is too much, so I just use the fan.

One of the first things I did when I got the car was pull the fan motor and oil it. (It was making noise) I cleaned it good at that time. Ever since, it throughs lots of air. My wife even commented the air comes out the door vents good. I do leave the blower on high because it helps it not freeze up.

[Helirich]

If you haven't already, maybe see that the stem is straight and moves??
.

The stem doesn't look straight and I don't think it moves. (In and out) When I use my fancy tool, I can unthread it about one and half turns. Then it just won't go any further. So I thread it back in before I remove the tool. I guess I could try unthreading it with a regular shrader tool, but I don't feel like getting a face full of freon if the threads strip all of a sudden. I have never run into a clogged shrader before. Leaking one, yes, but clogged no. I wonder if 40 year old dryer material could clog the port.

[Ron]

I see you're online...Can you chat a bit here now? I have may have an idea depending...

[Helirich]

I see you're online...Can you chat a bit here now? I have may have an idea depending...

What's on your mind?

[Ron]

1, Do you think your box is draining now?
2. If you were able to replace the shrader , what was you going to do next? check pressures or ?

[Helirich]

1, Do you think you box is draining now?
2. If you were able to replace the shrader , what was you going to do next? check pressures or ?

1. I've been fixing gutters on the house all day and repainting a "tanning ledge" on the swimming pool. Haven't even looked at the D today. So no, it's not draining.

2. Probably just take a drive and see if it freezes. (After I put the switch back in) Putting guages on only takes a second, so it might be nice to compare with your chart. I think we're expecting 90 degrees in three or four days. But I'm not sure I'll get to the car by then.

[Ron]

Sorry, fire pager went off...

I was thinking if you just wanted to see if it still freezes and/or make decisions etc., you might mount the switch at the compressor low side port and run a wire back to the front...

Edit: or better yet wire it in the engine bay

[Helirich]

Sorry, fire pager went off...

I was thinking if you just wanted to see if it still freezes and/or make decisions etc., you might mount the switch at the compressor low side port and run a wire back to the front...

That could be interesting. Wouldn't really want to keep it like that. If I get an extension on the drain pipe, I might try that. I did get my new accumulator. Just need time.

[Bitsyncmaster]

I never could get my AC cooling very well until I replaced that OEM drain hose with another design. That OEM hose puts a crimp in the elbow area like GM does the same on their units. I guess it's to limit air flow loss from the system. I did post that drain change on a thread here somewhere.

Beside that, I wanted to have the water drain away from the frame. I also can see the water after I park the car so I know the drain is still clear.

[Helirich]

Finally got the car up on ramps and found the drain hose. I can see it, but I can't really reach it. It seems to be draining on the edge of the fuel tank. I tried to pull it over, but it just springs back. I think I need to xtend it. The ramps aren't really tall enough, so I need to get it back on jackstands.

[WHO1DMC]

Just take the fuel pump access panel off to get at it.


Just an idea.
Dave B.

[Azar]

Just take the fuel pump access panel off to get at it.


Just an idea.
Dave B.But the hose is on the other side of the car?

Gesendet von meinem Mi 9T mit Tapatalk

[Helirich]

Just take the fuel pump access panel off to get at it.


Just an idea.
Dave B.

That's probably a good idea.


But the hose is on the other side of the car?

Gesendet von meinem Mi 9T mit Tapatalk

Not sure what you mean here. Is your car right hand drive? Even if it was, the access panel is in the center.

[Azar]

That's probably a good idea.



Not sure what you mean here. Is your car right hand drive? Even if it was, the access panel is in the center.Sorry, mixed it up with another access panel (under the tank cap).


Gesendet von meinem Mi 9T mit Tapatalk

[Helirich]

My thought was that you have to dump the Freon to change the accumulator. And changing it out involves the evaporator, which does not like to be disturbed and is a PITA to replace...]

Ok Ron, I'm comtemplating changing the accumulator. I assume you have done this. I see what you mean by disturb the evaporator. It will be real easy to put stress on it when removing the nut there. Do you know any tricks. You mentioned crows feet. I can see that maybe they might be useful. I tried to get some but none of the auto parts stores have any big enough. Not even Harbor Fraight. There is one outfit in town that might have them, but they were closed by the time I got there. I'll try there tomorrow.

I really really don't want to hurt the evaporator. Do you think that is likely? Or just possible? If it is likely, I won't do it now. I have a trip planned to NY at the end of the month. I would really like to take this car. If I break the AC, I can't take it.

It's kind of like everyone says "take care not to break studs when you remove the exhaust manifold". I took extra, extra care and only broke three out of six. I would say breaking a stud is not only possible, but likely. Please tell me breaking the evaporator is just possible, not likely.

Well actually, please tell me the truth.

[DMCMW Dave]

I really really don't want to hurt the evaporator. Do you think that is likely? Or just possible? If it is likely, I won't do it now. I have a trip planned to NY at the end of the month. I would really like to take this car. If I break the AC, I can't take it.
---
Well actually, please tell me the truth.

It is not uncommon to twist the end off the evaporator if it's frozen especially from a salty climate. Steel nut on aluminum threads etc. etc. Sometimes you win, sometimes you lose. That begins a Very Bad Day.

[Ron]

Ok Ron, I'm comtemplating changing the accumulator. I assume you have done this. I see what you mean by disturb the evaporator. It will be real easy to put stress on it when removing the nut there. Do you know any tricks. You mentioned crows feet. I can see that maybe they might be useful. I tried to get some but none of the auto parts stores have any big enough. Not even Harbor Fraight. There is one outfit in town that might have them, but they were closed by the time I got there. I'll try there tomorrow.

I really really don't want to hurt the evaporator. Do you think that is likely? Or just possible? If it is likely, I won't do it now. I have a trip planned to NY at the end of the month. I would really like to take this car. If I break the AC, I can't take it.

It's kind of like everyone says "take care not to break studs when you remove the exhaust manifold". I took extra, extra care and only broke three out of six. I would say breaking a stud is not only possible, but likely. Please tell me breaking the evaporator is just possible, not likely.

Well actually, please tell me the truth.Hmmm... "Possible" is way too weak and "likely" is a bit too strong. I would say it's "very risky" and avoid it if possible.

What I would do in your situation is get one of these:
66402 HERE (http://www.ackits.com/service-port-charging-adapters-mastercool/r12-adapter-90-deg-14-mfl-to-14-ffl-23702). Or 66403 HERE (http://www.ebay.com/itm/293625545944?hash=item445d7244d8:g:-YkAAOSwDvJe83mX).

Then pull the system almost all of the way down from the high side, remove the bad stem (gut it if you have to), quickly attach the adapter and switch, evacuate and dump 2.2 lbs in it.

[Helirich]

That is a good idea. I think I might even have something like that in my refrigeration tool bag. I'm going to try it today. I'll let you know how it goes.

Thankyou.

[dn010]

Since you enjoy cutting things so much, you can lower the risk by cutting the accumulator into sections to remove it. You can cut it in a way so that you're only left with the fitting to the evaporator and the rest is gone and you have room. There used to be photos and a writeup but the link to that particular section no longer works (http://deloreanreborn.com/).

[Helirich]

Since you enjoy cutting things so much, you can lower the risk by cutting the accumulator into sections to remove it. You can cut it in a way so that you're only left with the fitting to the evaporator and the rest is gone and you have room. There used to be photos and a writeup but the link to that particular section no longer works (http://deloreanreborn.com/).

That's not a bad idea also. Once you start cutting though, your committed. I'd rather do that when I get back from my trip.

Thanks!

[Helirich]

Hmmm... "Possible" is way too weak and "likely" is a bit too strong. I would say it's "very risky" and avoid it if possible.

What I would do in your situation is get one of these:
66402 HERE (http://www.ackits.com/service-port-charging-adapters-mastercool/r12-adapter-90-deg-14-mfl-to-14-ffl-23702). Or 66403 HERE (http://www.ebay.com/itm/293625545944?hash=item445d7244d8:g:-YkAAOSwDvJe83mX).

Then pull the system almost all of the way down from the high side, remove the bad stem (gut it if you have to), quickly attach the adapter and switch, evacuate and dump 2.2 lbs in it.

Update, I pulled the system down to low pressure. Tried to remove the stem by several means. No luck. So I got out the drill. Drilled through. Of course, there was a fair amount of pressure coming out when it finally went through. At least I can garentee no drill shavings went inside. I had safety glasses and gloves on, so I didn't get blasted too much. I quickly threaded the R12 elbow thing I got from autozone. (Special order) I was just like the thing you posted. (That outfit didn't answer the phone) I never let all the pressure out. Got the fitting on tight and pumped the system up again. Sprayed leak detector all over it. No bubbles.

So far, so good.

Now I threaded the pressure switch on by hand pretty tight. It fits really nice on the elbow. More out of the way than stock. I sprayed it down with the leak detector and I had lots of bubbles. So I tightened it some more. Still leaked. Got a wrench out and tightened it some more. Still leaked. Tightened it more and the switch busted. It was a one month old switch. It's a stupid design. It threads on a flarenut fitting, but there is no cone shape inside to tighten against. Of course being made of plastic doesn't help. I think I will look for a differnt switch. Might be a hassle because it's R12 threads. I do have a converter to 134 threads. But then the switch might be set for higher pressures.

In any case, I pressured up the system to 25 low and 190 high and it was blowing cold with the jumper in place. I have a short trip tomorrow. (100 miles one way) I'll see if it makes it.

I will say, even when I change the accumulator, I think I will use this elbow. It lays the switch over just right.

[dn010]

Might be a hassle because it's R12 threads. I do have a converter to 134 threads.

Huh?

You can get the pressure switch at most auto parts stores. There is nothing wrong with the switch design or being plastic, however, it will leak no matter what if you didn't put an o-ring on the fitting.

[Helirich]

Huh?

You can get the pressure switch at most auto parts stores. There is nothing wrong with the switch design or being plastic, however, it will leak no matter what if you didn't put an o-ring on the fitting.

I ordered one today from NAPA. Not for a Delorean. (No listing) It was for a 85 Corvette. I hope it works. Should be here in the morning. I'm not home right now. At relatives 160 miles away. The car gave me a scare. The guages started jumping all around. For some reason, I thought it was my newly installed alternator. Turned out to be the "dash services" fuse. I just took every fuse out and sanded them shinny last night. To heck with that. I just replaced them all with new today.

[Ron]

Sooo, how'd the AC do on your trip?

[Helirich]

Sooo, how'd the AC do on your trip?

I'm still on the trip. (The 175 mile trip, not to NY yet) I go back today. On this trip I'm just switching the AC on and off. I got a switch at NAPA, but it is slightly different. I will need to modify the spade end. So I'll be switching on the way home.

[Helirich]

Put the new switch on today and it is cycling. The temp out of the vents is about 50 degrees. Not quite as cold as before, but it doesn't freeze. The blowers are constant.

As far as the original post, I got an extension hard pipe to go over the side of the frame. Water should drain away now.

[Ron]

Evacuate it and charge it by weight and you'll be cool...

ST-29-11/81CATEGORY: TECHNICAL
ATTENTION: ALL DMC DEALERS/SERVICE MANAGERS
SUBJECT: FREON CHARGE AIR CONDITIONING
The freon charge has changed to 2.2 lbs. from the previous 2.75 lbs..
The new specification was introduced with V.I.N. 4080.
If knocking noises are observed during starting with the air
conditioning on, the new freon charge specification should be used.

[Helirich]

Quick question related to this thread. Does anyone know what size crow foot I need to remove the accumulator? I thought it was 1" and ordered one. Of course it's too small. I'm going to order another, but it's neerly impossible to measure in there. I'm guessing 1 1/16" or 1 1/8" , but maybe it's metric. It would be nice to get the right one.

Also, to anyone that has done it, will a "line wrench" work? (Like a crows foot, but more contact)

[Josh]

Its a 1-1/16, I just ground out a cheap wrench