Convert Your A/C System to Use an Alternative Refrigerant

[NightFlyer]

http://www.dmctoday.com/showthread.php?927-Convert-Your-A-C-System-to-Use-an-Alternative-Refrigerant

[Kenny_Z]

Nice write up and interesting alternative. One of the local owners is going to do the conversion to 152a at some point. I'm curious to see how it works in the Gulf Coast heat.

[NightFlyer]

Nice write up and interesting alternative. One of the local owners is going to do the conversion to 152a at some point. I'm curious to see how it works in the Gulf Coast heat.

Thanks - the tutorial applies to the big three popular alternative refrigerants - R-134a, R-152a, and 12a products, as ester oil is more miscible with all three refrigerants than the stock/OEM mineral oil.

When I reference not everything in the refrigerant can going into the system in the tutorial, this could very well be the bitterant that canned air manufacturers started adding to the product in reaction to the inhalant abuse epidemic (if you want to call it that - I prefer to call it simply dumb-asses being dumb-asses) - I honestly don't know for sure. It could also be other non-vaporizing impurities in the product. What that does mean is that it's absolutely necessary to tap a third 10oz can to obtain a full charge (you only use about 35%-45% of the refrigerant in the third can, depending upon how much you allow to vent to atmosphere from the first/second can while purging the charge hose and/or changing cans).

After adjusting the LPS to cut the compressor at the optimal low-side pressure (about 19psi according to the pressure/temperature chart), I was experiencing results so good that I was freezing the evaporator and had to up the LPS adjustment by about 3 psi to 22psi, which yielded about 42F vent temps at idle and an average of 37F while driving. The vent temps were experienced in 80F ambient temps with 87% relative humidity.

[gamerguy51]

Thanks - the tutorial applies to the big three popular alternative refrigerants - R-134a, R-152a, and 12a products, as ester oil is more miscible with all three refrigerants than the stock/OEM mineral oil.

When I reference not everything in the refrigerant can going into the system in the tutorial, this could very well be the bitterant that canned air manufacturers started adding to the product in reaction to the inhalant abuse epidemic (if you want to call it that - I prefer to call it simply dumb-asses being dumb-asses) - I honestly don't know for sure. It could also be other non-vaporizing impurities in the product. What that does mean is that it's absolutely necessary to tap a third 10oz can to obtain a full charge (you only use about 35%-45% of the refrigerant in the third can, depending upon how much you allow to vent to atmosphere from the first/second can while purging the charge hose and/or changing cans).

After adjusting the LPS to cut the compressor at the optimal low-side pressure (about 19psi according to the pressure/temperature chart), I was experiencing results so good that I was freezing the evaporator and had to up the LPS adjustment by about 3 psi to 22psi, which yielded about 42F vent temps at idle and an average of 37F while driving. The vent temps were experienced in 80F ambient temps with 87% relative humidity.

Great write up btw! I'm doing the conversion tomorrow if everything goes to plan, but one question. How to I disconnect the high side hose to the condenser? It's up in a pocket with a shroud covering it so two wrenches won't fit. Do I have to drop both radiator and condenser to achieve this? Thanks in advance!

[Bitsyncmaster]

Great write up btw! I'm doing the conversion tomorrow if everything goes to plan, but one question. How to I disconnect the high side hose to the condenser? It's up in a pocket with a shroud covering it so two wrenches won't fit. Do I have to drop both radiator and condenser to achieve this? Thanks in advance!

I cut away that shroud a little so the second wrench would fit.

[NightFlyer]

Great write up btw! I'm doing the conversion tomorrow if everything goes to plan, but one question. How to I disconnect the high side hose to the condenser? It's up in a pocket with a shroud covering it so two wrenches won't fit. Do I have to drop both radiator and condenser to achieve this? Thanks in advance!

Thanks :)

Dave M already covered the best way to access the condenser hose connections, short of dropping the entire assembly (shroud, fans, radiator, condenser).

Question though - why are you wanting to access the condenser?

[gamerguy51]

I just need to get the hose off to put on the new one.

[NightFlyer]

I just need to get the hose off to put on the new one.

Gotcha - best luck :thumbup:

[gamerguy51]

I am scared of cracking the connection... Cross your fingers

[NightFlyer]

I am scared of cracking the connection... Cross your fingers

Did the old one leak, or was it plugged up, or a bunch of fins damaged from impact with road debris, or something else that's causing you to change it out with a new one?

[gamerguy51]

Leaky hoses from both sides.

[gamerguy51]

Can you find wrenches this big that are cheap? My adjustable wrenches aren't cutting it?

[gamerguy51]

I'm afraid that the gas tank might have screwed with my leak sensor....otherwise I can't find where the leak could've been...

[Bitsyncmaster]

Can you find wrenches this big that are cheap? My adjustable wrenches aren't cutting it?

Most Auto Parts stores have some cheaper wrenches but best place to look are those tool discount stores. I think I used regular inch sizes and not metric.

[Ron]

Very nice write up! :thumbup:

$.02
In the thread you mentioned Bill being "100% correct"....using the engine vacuum to evacuate... There are several pros, mainly immediate cost, mentioned. A few cons are:

1. It is very inefficient -- The normal time is nowhere long enough to get a reasonable amount of the moisture out. It would be like using one of those campers Wick Candles to boil water in a pot v/s the campfire. Granted, a new accumulator will probably handle it. But it will be hard on it (desiccant).
It's not going to get it all with vacuum in the mid-low twenties.

2. There in nothing to prevent contaminants (from the engine) from flowing into the AC system.

3. It is illegal.

Depending on the existing refrigerant in the system, burning it with the engine can be:

3. Hard on engine/exhaust components (more significant w/ sensors, converters).

4. Expel highly poisonous gases (due to unintended temperatures etc.).

5. Damage the environment (ozone and not).

And:
6. :hatchet:


But, I will try the R-152A next time I get a reasonable chance ( guinea pig ;-)

[NightFlyer]

Very nice write up! :thumbup:

$.02
In the thread you mentioned Bill being "100% correct"....using the engine vacuum to evacuate... There are several pros, mainly immediate cost, mentioned. A few cons are:

1. It is very inefficient -- The normal time is nowhere long enough to get a reasonable amount of the moisture out. It would be like using one of those campers Wick Candles to boil water in a pot v/s the campfire. Granted, a new accumulator will probably handle it. But it will be hard on it (desiccant).
It's not going to get it all with vacuum in the mid-low twenties.

2. There in nothing to prevent contaminants (from the engine) from flowing into the AC system.

3. It is illegal.

Depending on the existing refrigerant in the system, burning it with the engine can be:

3. Hard on engine/exhaust components (more significant w/ sensors, converters).

4. Expel highly poisonous gases (due to unintended temperatures etc.).

5. Damage the environment (ozone and not).

And:
6. :hatchet:


But, I will try the R-152A next time I get a reasonable chance ( guinea pig ;-)

Bill admitted that it wasn't ideal, but rather stated that it was better than nothing and does work, especially if one found themselves doing A/C work away from the comforts of home. I noted in the main write up that if flushing through the accumulator, one would want to run whatever vacuum they were using for an extended period of time to assure that all moisture was removed from the system prior to charging. This is also why I added a fuel expense to Bill's cost estimate of his 'quick and dirty' / 'el cheapo' method. Thus, point 1 is well taken.

As to points 2, 4, and 5, while I understand the theory upon which you make them, I honestly don't see them as being anything more than negligible realistic concerns - especially for as seldom as one would be performing a full on flush and vacuuming of their A/C system. As to point 3, I don't understand why vacuuming with the engine would at all be illegal, unless this point relates to points 4 and 5, and while you'd be correct in such regard, it's also true that one trip on an airplane will cause more environmental damage than the average non-flying person will create in their lifetime, thus I don't exactly feel guilty about such, nor do I believe that such laws are at all equitable or even realistically enforceable against a shade tree mechanic, but that's just MHO.

As to point 6, well, it's always like that, as you know all too well :biggrin:

It has been almost a month since my last conversion attempt and the charge has held thus far :thumbup:

[Bitsyncmaster]

You don't want to use engine vacuum if you still have R12 in the system. It will put a white cloud of poison gas out the exhaust (I did that once). Vent or recover so the system is empty first.

[NightFlyer]

You don't want to use engine vacuum if you still have R12 in the system. It will put a white cloud of poison gas out the exhaust (I did that once). Vent or recover so the system is empty first.

+1

Venting/recovery is step 2 in the write-up :)

[Ron]

t
I noted in the main write up that if flushing through the accumulator, one would want to run whatever vacuum they were using for an extended period of time to assure that all moisture was removed from the system prior to charging.Personally, I would have to re-evacuate and replace the accumulator/receiver-dryer if I gave in due to "doing A/C work away from the comforts of home". And then I'd only do it on my own vehicle. But that's just me I guess.

Anyway, normally, you can not get the moisture out of the desiccant, it catches the moisture not like a "filter" but bonds with it. That's it's job. If you do get it hot enough, the sack etc (container) is compromised/destroyed...

I am with you on WRT the environmental damage aspects [Did ya catch the 'joke' over the latest findings...they now say that, assuming the concerns are true, it would be a good thing for the trend to continue until 2070 because it is good for plant life..., fortunately they named it the "greenhouse effect".
I am amazed how people don't look at how many times it has been said, "Well we now know that was not true...", even concerning what we eat, what, dozens of times. Not to mention who is investing in green energy and...ah, I'm digressing into rule/troll hell....]

As for point 3 ( I mis-numbered when editing, sorry) The first #3 (poison) is significant. It is not like the "effects of accumulation if everyone did it" environmentalists complain of -- People have been sent to the hospital over it ie it is bad ass when burnt with flame, not to mention along with gasoline and the temps involved.
Maybe, if venting meant blow it out entirely...
And for he second #3 (damage), it would take several repetitions to do significant damage to the engine itself, but with sensors like the O2 on a D, and others on newer vehicles, it is definitely asking for it.



As to point 6, well, it's always like that, as you know all too well :biggrin::biggrin:

[gamerguy51]

Hey guys, as per this threads tips I had to find a set of wrenches that both can fit in the tight spaces and come in non-common sizes of the a/c connections in this car. I found the perfect set at Harbor Freight for 50 bucks. I also bought a 2ft iron pipe for a cheater bar. I knocked out those fittings pretty easily considering how hard I was expecting it to be.

Also, i "flushed" my system with mineral spirits as per dmctoday's youtube video and was on my second quart when I decided to bump up my psi to 100 and proceeded to spray mineral spirits into my face and all over my engine bay...here's a tip, stay at 50 psi. Also the accumulator, hoses, and evaporator still had at least 10oz of mineral spirits in the system after I took it all apart. It was okay since I was replacing most of it and then blew out the rest at the source. It's probaby a better idea to flush at each component around the accumulator even though putting it back is hell of a pita.

Here's a link to those tools if you guys are interested!

http://www.harborfreight.com/15-piece-sae-service-wrench-set-93667.html

[Bitsyncmaster]

Nice find on that wrench set. I don't think I've ever needed larger than 1 1/4" but that set looks like something I may buy someday.

[spikeygg]

This is a very thorough write up, I really dig the amount of detail having no experience with doing A/C stuff I plan to learn using this guide. I have a question though. I know we have the schrader valves from the factory and I just found that SpecialTAuto sells R12-to-R134a quick disconnect fittings that appear to go over the stock ports:

44903 (http://specialtauto.com/delorean-parts/images/AC-adapter-R12-R134aA-strai.jpg)

I just bought the harbor freight A/C discharge/recharge manifold gauges set and it came with the quick disconnect ends but, obviously, I cannot use them with the stock parts. Anyone know the usage details around the SpecialTAuto parts? Do you pull the shrader valves and rely on these new caps to seal the system? I'd like to be able to use the quick disconnect if possible, in my mind it seems like it would be easier to avoid contamination than using the screw on fittings...

[Andrew]

This is a very thorough write up, I really dig the amount of detail having no experience with doing A/C stuff I plan to learn using this guide. I have a question though. I know we have the schrader valves from the factory and I just found that SpecialTAuto sells R12-to-R134a quick disconnect fittings that appear to go over the stock ports:

44903 (http://specialtauto.com/delorean-parts/images/AC-adapter-R12-R134aA-strai.jpg)

I just bought the harbor freight A/C discharge/recharge manifold gauges set and it came with the quick disconnect ends but, obviously, I cannot use them with the stock parts. Anyone know the usage details around the SpecialTAuto parts? Do you pull the shrader valves and rely on these new caps to seal the system? I'd like to be able to use the quick disconnect if possible, in my mind it seems like it would be easier to avoid contamination than using the screw on fittings...

Conversion fittings are a standard part and not Delorean specific. Most parts stores sell the adapter fittings. They are normally on the seasonal A/C rack. After 1977 or so, domestic auto manufacturers (I know GM for sure) started using a smaller size fitting on the low side, this was likely done to prevent novices from trying to charge the high side and blowing up the can in their face. Import autos such as the DeLorean continued to use the same size fitting on the high and the low sides. Thus the kit that you will need will be packaged as (Domestic through 1976 / Import)

With regard to the Schrader valves, every low side conversion fitting I've ever seen has its own dedicated Schrader valve. Thus you use a Schrader valve puller (same tool as a tire valve core puller) to remove the low side Schrader before installing the adapter fitting. In contrast I have seen a lot of hollow high side conversion fittings that simply screw on top of the stock high side fitting, thus the original high side fitting is re-used after the conversion.

[DMCMW Dave]

With regard to the Schrader valves, every low side conversion fitting I've ever seen has its own dedicated Schrader valve. Thus you use a Schrader valve puller (same tool as a tire valve core puller) to remove the low side Schrader before installing the adapter fitting. In contrast I have seen a lot of hollow high side conversion fittings that simply screw on top of the stock high side fitting, thus the original high side fitting is re-used after the conversion.

There are some crappy aluminum fittings out there that don't have a full Schrader in them, just a pin to press the one underneath. Avoid them like the plague. The best ones are steel, in that case you remove the original Schrader and leave it out.

[dodint]

Do the DMCx vendors still service R-12?

From my BMW days a stock R-12 system will outperform even a properly setup R-134a system, it's just the nature of the material. The main reason for converting to R-134a was for convenience.

Does that hold true for the DMC? If you buy a car already converted could you convert back if you were unhappy with the performance? (NOS parts available, legality, etc)

[DMCMW Dave]

Do the DMCx vendors still service R-12?

From my BMW days a stock R-12 system will outperform even a properly setup R-134a system, it's just the nature of the material. The main reason for converting to R-134a was for convenience.

Does that hold true for the DMC? If you buy a car already converted could you convert back if you were unhappy with the performance? (NOS parts available, legality, etc)

Depends on the vendor.

The only issue with converting back would be the unknown cocktail of oils in the system. If the conversion was done properly (with POE oil) it would not be too bad to flush out as traces of that would mix OK with the mineral oil. If someone flushed and converted it to PAG oil, it's really hard to get it all out and it does not play well with mineral oil.

[content22207_2]

Two words: Ester Oil.

Ester is 100% compatible with OEM mineral oil (and mineral spirits if you use that as a flushing agent) and R134 refrigerant.

All parts houses sell it.

Bill Robertson
#5939

[Bitsyncmaster]

There are some crappy aluminum fittings out there that don't have a full Schrader in them, just a pin to press the one underneath. Avoid them like the plague. The best ones are steel, in that case you remove the original Schrader and leave it out.

+1
The aluminum will bind when you install or remove them. You never know if you have them screwed on tight enough. The steel ones are made so much better.

[Henrik]

Two words: Ester Oil.

Ester is 100% compatible with OEM mineral oil (and mineral spirits if you use that as a flushing agent) and R134 refrigerant.

All parts houses sell it.

Bill Robertson
#5939

Sanden has never validated their compressors with ester oil. Refer to sanden.com

[Rich_NYS]

There are some crappy aluminum fittings out there that don't have a full Schrader in them, just a pin to press the one underneath. Avoid them like the plague. The best ones are steel, in that case you remove the original Schrader and leave it out.


+1
The aluminum will bind when you install or remove them. You never know if you have them screwed on tight enough. The steel ones are made so much better.

+2

[Dave M,] remember my A/C at DCS 2014? One of those cheapie valves was causing an issue when Bill was trying to charge the system. We got it [temporarily] working by replacing it with another crappy [new] one from Autozone. When I got home I replaced it with a nice steel one from NAPA and everything was golden. I later gave the new cheap aluminum one to Bill; he kept it onhand as a giveaway in case he ever encountered another owner in need and no parts store nearby.

[content22207_2]

I'm carrying it in my cubby in case I ever encounter an R12 car that needs use of my R134 pressure gauge -- I'll screw it on long enough to use the gauge, then remove it.

Bill Robertson
#5939

[spikeygg]

We got it [temporarily] working by replacing it with another crappy [new] one from Autozone. When I got home I replaced it with a nice steel one from NAPA and everything was golden.

Damn, I just got back from NAPA and Autozone. I went to NAPA first and they said they'd have to special order it (no stores in town carry it)! The guy suggested Autozone or O'reilly. Then I went to Autozone and saw the cheapo aluminum for like $13. I didn't buy it, I want the steel ones where else can I go? I don't have a Pep boys but I do have O'reilly, I'll try that I guess. :(

[Rich_NYS]

I'm carrying it in my cubby in case I ever encounter an R12 car that needs use of my R134 pressure gauge -- I'll screw it on long enough to use the gauge, then remove it.

Bill Robertson
#5939

Bad recollection on my part.....

[spikeygg]

I just when to O'Reilly auto store, they had a few options for fittings but they all looked like they were aluminum. Where else can I go to find the steel fittings?

44930

[content22207_2]

These are the NAPA fittings you want:

44933 44934

If my small town NAPA has them, they should be available nationwide.

Bill Robertson
#5939

[spikeygg]

These are the NAPA fittings you want:

44933 44934

If my small town NAPA has them, they should be available nationwide.

Bill Robertson
#5939

Awesome Bill, exactly what I needed. Thanks again!!

[cdrusn]

The aluminum valve fitting will not break. You always have to be careful when connecting the gauge fitting to the valve because the line the valve is attached to is aluminum and weak, you are more likely to crack the line than the fitting. You always take out the original schraeder valve when topping it off with a conversion fitting otherwise it might bend the fitting underneath it and you won't be able to fill the system. Make sure you put in a can of green dye so you will be able to see a small leak should it occur. :race:

[content22207_2]

You always take out the original schraeder valve when topping it off with a conversion fitting

Negative on cheap aluminum ones. Hold one up to the light -- you can see right through it. They don't seal anything by themselves. What looks like a schrader valve is just a pin that flexes in a bent piece of metal. There is open space on either side of the metal piece.

Bill Robertson
#5939

[Michael]

I picked up a nice working r12 machine for 100 bucks and another 100 bought me 18 cans of R12 replacement and a few cans of oil charge. I bought this over a year ago and haven't used it yet, but it's nice knowing I have it in case, especially with R-12 service being all but extinct these days.
44942449434494444945

[spikeygg]

These are the NAPA fittings you want:

44933 44934

If my small town NAPA has them, they should be available nationwide.

Bill Robertson
#5939

I went to NAPA and bought both 409901 (https://www.napaonline.com/napa/en/p/TEM409901/TEM409901) and 409903 (https://www.napaonline.com/napa/en/p/TEM409903/TEM409903) and brought them home. When I tried to thread them onto the high and low side ports I couldn't use them both. I found that the ports on my system are both 1/4", the blue topped one (409903) worked with both ports. 409901 is apparently 3/16" and was too small for my high side port. I went online and I tried manually searching for 409902 (https://www.napaonline.com/napa/en/p/TEM409902/TEM409902) which happens to be the 1/4" version of 409901! :)

So I pull the schrader valves and just thread these onto the ports with some teflon tape? Is that the acceptable method for permanent installation of these fittings?

Thanks,
-Greg

[DMCMW Dave]

I went to NAPA and bought both 409901 (https://www.napaonline.com/napa/en/p/TEM409901/TEM409901) and 409903 (https://www.napaonline.com/napa/en/p/TEM409903/TEM409903) and brought them home. When I tried to thread them onto the high and low side ports I couldn't use them both. I found that the ports on my system are both 1/4", the blue topped one (409903) worked with both ports. 409901 is apparently 3/16" and was too small for my high side port. I went online and I tried manually searching for 409902 (https://www.napaonline.com/napa/en/p/TEM409902/TEM409902) which happens to be the 1/4" version of 409901! :)

So I pull the schrader valves and just thread these onto the ports with some teflon tape? Is that the acceptable method for permanent installation of these fittings?

Thanks,
-Greg

IF the fittings are any good there is a o-ring inn the female side, and the Teflon tape isn't necessary. In fact, most of the "good ones" have some pre-installed dry locktite on the female threads.

[Morpheus]

I went to NAPA and bought both 409901 (https://www.napaonline.com/napa/en/p/TEM409901/TEM409901) and 409903 (https://www.napaonline.com/napa/en/p/TEM409903/TEM409903) and brought them home. When I tried to thread them onto the high and low side ports I couldn't use them both. I found that the ports on my system are both 1/4", the blue topped one (409903) worked with both ports. 409901 is apparently 3/16" and was too small for my high side port. I went online and I tried manually searching for 409902 (https://www.napaonline.com/napa/en/p/TEM409902/TEM409902) which happens to be the 1/4" version of 409901! :)

So I pull the schrader valves and just thread these onto the ports with some teflon tape? Is that the acceptable method for permanent installation of these fittings?

Thanks,
-Greg

I wish I would have seen this post before I ordered 409901 and 409903. Thanks for posting the correct part number, sir!