AC Conversion for an '87 Caprice Wagon?

We have had some really hot weather over the past several days here in So Cal and I've noticed my AC is not quite cold enough. So I'm looking at possibly having to convert my AC to R134 from my original R12 since it's no longer available. Does anyone have experience doing this professionally? I'm curious to know what equipment changes will be necessary (how big of a job is this?). I'm expecting my first quote from my mechanic in a few days.
Thanks in advance for your thoughts/advice.

 

Ultimately provided the system is not leaking, what you have to do is evacuate the existing system, drain all of the oil out of the components (compressor included), then refill with R-134a at roughly 80% of the total volume (by weight) of the R-12 volume, and add the proper amount of oil (PAG or ester oil) and you should be good to go. Since you have to tear down the system to get the old oil out, you're best off replacing all of the barrier hoses (R-134a is a smaller molecule than R-12 so it leaks easier plus 30+ year old hoses are old and should be replaced), replace all of the o-rings, the desiccant bag in the accumulator, and verifying no leaks for 24 hours. If you want to get super fancy a cross-flow condenser is advised as they are better suited to R-134a.

Biggest thing to be aware is that the heat transfer of R-134a is higher than R-12, and the pressures are slightly higher. So your system seals have to be good or new and your airflow through your condenser needs to be better than with R-12.

 

Go to the the 4 Seasons website http://www.4s.com/en/ and scroll down until you hit the tech tips. There are a number of pdf's concerning the conversion.

 

Thanks Guys!

My mechanic just asked me to swing by so they could take a look under the hood. Good news at first was someone already converted it to 134. Bad news is they did a half-a$sed job. Some of the fittings are still R12. And the compressor needs replacing. I want this done right so I may go for a whole conversion (over again).

 

Well luckily, the GM compressors are well-suited for a 134a system, so replace both it and the accumulator-dryer with parts from a newer Caprice/Impala (I'm guessing yours has the V5 compressor). Then, as elB said, replace all the hoses and o-rings to to tight-barrier hose and HNBR (green) o-rings. Here's a link to a specific page for doing GM; bear in mind, some of the info is now outdated, so show this to the service techs and discuss it with them.

www.e38.org/parish/gm-rp.htm

 

Ah, that would explain why I've been seeing green hoses more often lately lol. Thanks Andrew! I'm going back on Monday to talk with my tech.

 

Green hoses? That's a new one on me. I've only been off working for three years as of today.

 

My 1992 Caprice Wagon has never been converted to R134.

Some of my cars, I converted back to R12 equipment.

Do I run R12? No. I run ES12 Industrial refrigerant.

Colder than R12. Colder than R134. Head pressures similar to R12.

There are those who will knock the ES12 because it is a propane based refrigerant. Fact is, I was involved in a descpicable front-end collision running ES12 in my old '87 BMW and despite everything forward of the front doors being destroyed, there was no fire, explosion, or anything.

Here in Florida, we have to deal with a lot of humidity on top of the heat. R134 conversions work out well in the dry states, but here in FL, their weaknesses are quickly exposed.

I run into people alot who have those fancy conversions done to their old Chevies, including Sanden compressor, parallel flow condensor, and variable orifice tube. My ancient R4 compressor and factory tube-and-fin system blows their doors off.

 

I take Wikipedia entries with a grain of salt, but one should make an informed decision:

You can't prove a negative. Just because you were lucky doesn't make this a good idea. That's like saying that because you haven't hit a deer, you've proven that deer whistles work. Lots of Ford Pintos got rear-ended without blowing up...

 

It is illegal to use non-automotive refrigerants in your car. It can cost a shop their license from the EPA to do business if they get caught using the stuff. You can use it all you want at home by yourself, but no shop will touch it. It actually doesn't leak normally nor does it catch fire when it does, but the ability of it to do so exists and the powers that be have made it illegal to do for that reason.

 

Not only can a shop lose its license, heavy fines go with the infractions. The fact that you have that refrigerant in your car opens you to a hefty fine also, if caught. The last time I went througb an A/C refesher training class, the instructor told us that infractions on R-12 systems was $10K per infraction, and mixing any contaminating refrigerant the same, but installing non-approved refriverant in any automotive system whether by shop or car owner, carried a $50K penalty per infraction.

 

And that was about or over 15 years ago, but I'm very sure the laws have not changed. It took me a couple years to convince my dad not to do the same thing down in Mexico at around that time when he lived there.

 

I love it when people assume I have not done my homework.


1. R134a IS FLAMMABLE and has a LOWER auto ignition temperature than ES12 refrigerant. The oil that is used in automotive AC is even lower than that. R134 will burn faster than ES12 Industrial will. The oil in both with go up like a Roman candle when it escapes as a gas from any leak or rupture.

2. Any R12 system that has been evacuated and has R134 fittings screwed onto it is legally considered an R134 converted system, and ES-12 is 100% legal for use as an R134 substitute in automotive AC systems.

3. Finding a shop that will service an ES12 equipped vehicle is not hard. I've been working on and driving propane powered vehicles my whole life. There are plenty of people out there who do not mess their pants at the idea of dealing with a hydrocarbon system.

4. In a propane powered vehicle, propane is circulated and HEATED with engine coolant in the engine bay. There's no reports of those going up like Mt. St. Helens, even with a 40-60 lb. reservoir feeding the whole deal. 2 lbs. of a sunstantially less flammable refrigerant in the engine bay isn't nearly as scary.

 

First, I have no personal knowledge or experience with ES12. My only point was that the OP needs to educate himself and make his own informed decision.

Second, comparing propane in a fuel system to propane in a refrigerant system is both disingenuous and inappropriate. Fuel systems are designed to handle flammable fluids and thus use materials and line routing that provide some measure of protection in a crash. Automotive refrigerant systems are not intended to provide the same level of protection.

Again, I am NOT criticizing the use of ES12 or any other refrigerant, so don't take this as an attack on your manhood, but your safety rational is flawed.

 

Automotive refrigerant systems are designed to handle a fluid and gas that is actually more flammable than ES-12, so there is not an issue there.

My comparison is neither disingenuous or inappropriate, because my comparison made no reference to crash performance at all. My comparison spoke only to the capacity of propane's ability to exist in an engine compartment without creating an undue hazard. There is no rocket science going on there either, with regards to the tubes or hoses. If a wreck occurs, the tubes and hoses are no more durable than any other type of hydraulic-style tube or hose.

R134a auto-ignites at 400F @ 5psi with oxygen present. R134a has the capability to turn into a fireball simply by leaking in the area of the exhaust manifold. Combined with the oil, this combo is about as bad as it gets. Beyond that, R134a is extraordinarily toxic when it burns.

The is the very reason you can use HC-12 to replace R134a, but not R12. It's more flammable than R-12, but is a total sweetheart compared to R134a.

My only point is: ES-12 places you at no greater risk of fire than R134a itself, making any flammability concerns about converting to either a completely, entirely, unequivocally moot point.