Air Conditioning - R12 Replacement

[cort1977]

Having trouble finding good information on what refrigerant gas to use on the Pontiac air conditioning.

 

Last summer I was parked with the AC on as my youngest was asleep in the back.   Wife had 'just popped in to the supermarket for a few bits'.   After half an hour of patient* waiting the AC hose burst and all the gas escaped.

 

Local AC place advised the old R12 refrigerant was banned and to change over to a replacement I would need to change the hoses and get a replacement refrigerant.   The R134a used on moderns isn't compatible with R12 so may react with residue in the system, need to replace the filter drier, O rings etc.

 

There are various refrigerants marketed as 'R12 replacement' that work but are propane/butane mixes.   Given what happened to the hoses before I would be a bit concerned about suddenly venting a lot of flammable gas under the bonnet.   On the other hand, there's plenty of flammable petrol vapour under there already.

 

Thoughts?

 

 

[Split_Pin]

Tbh I would entrust this sort of job to a local garage especially if you have a little 'un. I presume you can source the new parts yourself and just hand the lot over?

 

On the other hand the A/c stopped working on my Astra years ago and I have just left it alone.

[cort1977]

Yep, want them to vacuum the system and would be happy to hand the whole thing over, they just don't seem to want the job.   I suspect the whole thing has the potential to go wrong and they don't want the hassle.

 

It will be 100 degrees and 100% humidity here soon so need to get it sorted.

[cort1977]

Ha!   Never realized that lunatic lived in H-town.  

[BorniteIdentity]

Read up on R24.

 

I have this problem with my 190e and I'm pretty confident this is the best solution.

 

Good luck and let me know how you get on.

[MikeKnight]

Same problem with my Toyota Supra Mk3.

 

Thankfully the AC still works but it's like a slightly colder asthmatic breathing on you. Needs re-gassing.

 

I'll get around to properly converting it to a modern gas... eventually. Lot of work to do on it before then.

[cort1977]

Read up on R24.

 

I have this problem with my 190e and I'm pretty confident this is the best solution.

 

Good luck and let me know how you get on.

Thanks for that.   Having read up on it I also think it's the best solution.   Had a good look around and turns out it is not available in the US.  

 

Apparently, one of the component gases, R-218, has a Global Warming Potential (GWP) of 8680 compared to CO2.   Because AC in the US is often 'fixed' by filling up with a can of refrigerant every few months the EPA doesn't want to approve R24.   They also have a complex approval process, the SNAP program, for approving R12 replacements that doesn't cover R24 at present and likely won't ever as the number of R12 systems declines. 

 

As far as I can work out the available options are change to R134 with all the compatibility issues or go for a propane/butane mix such as 'Enviro-Cool' and run the risk of a flammable gas in the system.

[mat_the_cat]

Sorry to sound pedantic but are you looking for R-24 or RS-24? I use RS-24 (R-426A) in the BX as a drop in replacement for R-134A.

 

Failing that, can you get R-413A over there?

[cort1977]

I looked for both R-24 and RS-24, not available.   R-413A (Isceon M049) is also not available.

 

Unless a refrigerant is on the EPA approved list for cars they are not easy to find.   Other hydrocarbon based refrigerants like R-12a can be sold but are technically illegal to put in cars over safety concerns.   It would explain why my local AC place was a bit cagey about supplying alternative refrigerants although they said they would put in what I supplied.

 

Even R-134a is apparently on the way out according to the latest EPA rule which runs to 101 pages.   The new one is R-1234yf already going in to new cars.

[PhilA]

Head this way. You can still fill up R12 here with a license for it in LA. It is expensive though, but often cheaper than replacing everything.

 

Phil

[SiC]

Isnt r134 flammable with refrigerant oil anyway?

 

Given you have a tank full of petrol and a pump forcing it into the engine bay, is a couple hundred grams of hc12a gonna make much difference to that mix?

[cort1977]

Yes, I have read that R134a is flammable with the oil vapour it contains in a working system.   You're right about the flammable materials in the engine bay already, I don't think it is a huge risk but I thought I would ask on here to canvas opinions.

 

Phil, didn't know that you could still get R12 in La, Lake Charles is only a couple of hours from here.  

 

I will go and have a much more informed chat with my local AC specialist.   I'm not sure that I have many components that need replacing for a change for example, it's all hardlines except for two hoses that are cheap to replace with regular barrier hose and the dessicant which is probably good practice to change anyway.

[hauserplenty]

To repair it properly, you either need to replace the entire system with an R-134A compatible system, or lob some fresh R-12 in. You can then have the existing system:

1: Flushed.

2: Vacuum tested.

3: Refilled with the correct blend of 'fridgerant an' oahhl.

 

You should likely also need to replace the receiver-drier, as you've already sussed. If the system has been left open for even a few hours, it can become contaminated with moisture.

 

Of course, never mix refrigerants, and IMHO, installing R-134A into an R-12 system is a complete waste of time and money. The higher boiling point of R-134A requires greater surface area than the evaporator and condenser you now have. It may work at 80 degrees, but not so well (if at all) at 90-100.

 

It's bad luck, but if you like the car, and you must have A/C, you have only two choices, both of which are expensive.

[cort1977]

So if anyone is still interested I spoke with my local AC man again this morning.   After talking with his son who is not the brains of the outfit the old man eventually came out for a chat.

 

He flat out said that it was not worth replacing parts and trying to use R134a as the old systems don't like it as advised by hauserplenty.

 

He did then grudgingly admit that me might have some R12 tucked away somewhere and that if I replaced the receiver drier desiccant and put on new hoses he could vacuum and refill the system.

 

The cost for this is likely to be close to Liberia's national debt, on the other hand so is a completely new retrofit system and AC is a need not a want down here.   So it's going in next week.

 

Thanks for all the advice and information, I have learnt a lot about AC.

[SiC]

Reckoned he squirrelled it away for his classics?