Type_LT

I would like to convert my system to R134a. The AC system was working a year ago however it stopped and apparently has very little if no freon in it, good time to convert. I found a conversion kit for ~86.00 on partsamillion.com. I'm looking for any advice on where to get a good kit, or how hard the processes is or just anything anyone can tell me Thanks.

billybones

I have no idea about conversion kits.. Just make sure you find the leak first.. and do not run the compressor without any refrigerant. it is what carries the lube.

Dan in Pasadena

LT- I still haven't done this yet even though I already bought the kit. Just got too busy with other stuff. Use the Interdynamics kit available from WalMart- yes, WalMart. It's about $35.

There is an old thread about this subject and I have a hard copy somewhere. I'll try to find it and give you the "pertinents".

One of the guys on the board has done this and said it went flawlessly.

Bob S. 1984 Silver

I may be the guy Dan refers to. I used to service A/C automotive units (EPA certification), but gave it up when I relocated to Tucson. My '84 944 was converted three years ago with an Interdynamic kit which includes the oil, sealant and initial charge, although nearly two additional cans of refrigerant will be required. The system will require evacuation which cannot be done legally by venting to the atmosphere. A hard vacuum has to be applied to the system and held for one or two hours. This must be done by a qualified shop. Simply opening the system will introduce air with moisture and do damage. If the system cannot hold the vacuum, then parts require repair/replacement.

It works here in Tucson, even at 105 degrees in the summer.

Good luck

Bob S.

Renntag

I agree with BOB, Vacuum test is paramount.
Evac the system.
I'd replace the Drier.
if you need a compressor get a Sanden conversion.
The biggest difference is the oil and the fittings.
R134a isnt as efficient as R12, but oh well.
The conversion is simple.

I did my GTI, My previous N/A, 2 other VeeDubs for family members, and my 951.

Good luck.

951and944S

I've done this 3 years ago, on my S, works fine since.
134A doesn't have the cooling ability at idle though, but it's great at road speed revs.
It runs at a higher psi, and the compressors designed for it have a higher "blowoff" safety valve on them, if I remember right.
Griffith's makes a larger evaporator for the "not so cool" at idle problems.
Personally, to me it's not really a problem.
A/C techs will say, the "o" rings used for the R12 are not compatible with the 134 and will fail, soon after the change, but while I DID change all of mine that were easily acessible, some, (expansion valve area) are virtually impossible to get to.

twat

Bob S. was fortunate enough to have a good experience with 134…. but don't forget that your car was originally designed to use a refrigerant of much higher efficiency. 134 is perfectly suitable for later (post '94) cars originally designed to use it. These later cars have larger condensers, larger evaporators, orifices (or TXVs) designed for 134 and a capacity for greater system pressures. Another key factor is O-ring material. R12 systems, like yours, use mineral oil for lubrication. The O-rings are regular butyl rubber. When you use the PAG oil that usually comes with the conversion kits, you run a significant risk of compromising the reliability of the O-rings because PAG oil deteriorates butyl. The other lubrication option is ester oil, which is OK for butyl but makes a horrible compressor lube. Since 134 is less efficient than R12, you will have noticeably higher vent temperatures and higher system pressures. Higher system pressures are more taxing on the compressor and they create a higher possibility of leaks. In addition, 134 is a much smaller molecule and is therefore prone to seepage through seals. R12 is a far superior refrigerant for your system…it's just really expensive. As you may be able to tell, I wouldn't recommend R134. But if you do use it, do as Bob S. suggested pull a long deep vacuum, somewhere in the neighborhood of 30" of water (2.75 hg) for an hour. This is absolutely essential and it's easy to do if you have a vacuum pump. And since you'll be pulling a vacuum, you may as well change your dryer bottle too. If you're really ambitious, you may want to flush the system and replace your old O-rings.
Now there is an alternative solution to all of this, PLEASE NO FLAMES HERE: hydrocarbons. Yes, hydrocarbons. The same gases that you use for your BBQ and cigarette lighters. A 60/40 mix of clean propane and isobutane makes an EXCELLENT refrigerant. This mixture has the same pressure / temperature characteristics as R12. It carries mineral oil very well. It is an extremely efficient refrigerant allowing for very low vent temperatures and less pumping time for the compressor. It runs low system pressures which results in less overall system stress. Another advantage is that moisture does not create corrosive acids like with R12 and R134. The molecules are huge so leaking over time is not an issue. Hydrocarbons are 100% ozone friendly they are very INexpensive. If you want more info I'd be happy to help, just no flames please…

Tabor

****, I am very interested to learn more about hydrocarbon refrigerants. I have a few questions:

1. Where do you get them.
2. How do you charge your system with them.

I see #2 as the hardest. I don't think my local AC shop will pump seemingly random flammable gas into my AC system for me.

twat

Well Tabor…first, don't mention hydrocarbons to any A/C technician, please. Everything I'm mentioning is all perfectly legal in the US but A/C shops dislike hydrocarbons because they create liability (sort of) and reduce profit margin but that's another story; again that's my HO so no flames. If you do go with hydrocarbons, you must do everything yourself (which is easier than replacing your motor mounts).
You can source the gasses in many ways. Propane is easy. Isobutane (NOT butane) is not so easy but it is available usually as cigarette lighter fuel or camping stove fuel. Do not use blends like isopro or the others because you won't have a reliable ratio to work with; this is critical. I'll stop there because it gets 'involved' after this point and requires information that goes well beyond the scope of this thread. As far as conversion, it's cake. Purge your system of all remaining R12 (at an A/C shop, of course), change any suspect O-rings with regular old butyl rubber, pull a vacuum, refill your compressor with the factory specified quantity of mineral oil, and recharge with the hydrocarbons. You may want to clean all system components if you've had a compressor failure. You'll need a whole host of inexpensive fittings, a vacuum pump and a good digital scale to do this. BTW, a very effective vacuum pump can be fabricated from an old refrigerator compressor. The gas required to fill your system will cost around $12 and it will turn your car into a meat locker regardless of ambient temp/humidity. Want more? I'd be happy to help.