Hi all

I have a 1985 coupe. After 8 years I have taken it out of storage and got it back on the road. When i drove it last the AC worked great. Now Nothing. I am thinking of just having the system evacuated the recharged with a can of oil and the R12 freon.
Anyone have any thoughts? Anything I should look out for?
Any help would be great. I have a shop that works on AC all the time but wanted to get other opinions

Thanks

 

If you have a relationship with the shop and considering the "storage" I believe it wise to let them do a proper evacuation, evaluate and then charge. Pass on to them what you've mentioned here and they should be able to advise.

If you've no experience with them maybe you have a conversation with them and bring their suggestions back here for a discussion.

 

Before you just recharge, I would definitely check why it is not working. Is it a switch somewhere or is it a leak. If it is a leak, I would pull the charge out, fix the problem and then put a receiver dryer on it, fill and test. I really wish it mine wasn't converted to R134A. I have yet to see a conversion that cools as well in blazing hot weather driving start and stop yet.

 

on checking the HP/LP cycling switches, and while it may not cool quite as much as R12, my 134a conversions gets pretty friggin' cold - hot, humid, and in florida...



40.5° cruise, about 55° in stop/go traffic, and outside temp, around 90° -- it may not be perfect, but it works for me....

 

Check for a leaky shrader valve.Mine had a small leak on the high side.Replaced valve,good to go!

 

Not a "may not". More of a "will not" from what I have seen.

What do Florida people know about cooling? Had a bunch of people from FL and TX here before and they were freezing because the night was mid to low 60s. My folks from SE Asia were opening the house up at 85 and wearing light sweaters. My dogs had their tongues out and were panting away. I had to shut all doors and windows and turn on the AC and run the fireplace in the basement where their room was for them to be comfortable.

 

whatever...

 

As said, if you have an electrical problem you have to address that before you can charge the system.

However if the system is so low on Freon that the low pressure switch does not close to turn on the compressor, I would at least take a good look for a leak at the compressor due to the fact it was sitting so long and the operation of the compressor may have let all the gas leak out at the shaft seal.

 

You are kidding, right?

 

You saw the , what do you think?

 

Might I suggest getting the shop you deal with to check to see if the system has any pressure in it? (If you have a R12/R22 gage set - it's about a minute and a half job). If the system is holding pressure - put 12V to the compressor and see if it engages - if it does - look for the electrical issue that is preventing the compressor from running. There are a number of cheap things it could be. If the compressor won't engage with 12V to it's coil - I think you know where your problem lies.

If the system has no pressure in it - pull a vacuum and see if the system will hold vacuum. If not - the next step is to find the leak - if it does hold vacuum - that would be the time to think about a R134 conversion. There is really no question that the R134 conversions DO work - but when the factory went from using R12 to R134 - they did make some changes in the system to help it work BETTER.

 

Why? Is R12 so much more expensive?

Define "work". If by "work" you mean is it cooler than nothing? Absolutely. If by "work" you mean "Is it cooler than R12 on the most punishing of days, well, I haven't seen it yet. On 75 degree days, probably won't notice much. 80 degree plus days in stop and go traffic, this I gotta see.

"Better" is another elusive term. I can make it cool as well as a system designed with R134A from scratch but would it be cost effective? Your system was designed with R12 in mind and not R134A. I can change the orifice valve to one better suited but I think it was mentioned that you are going to need a more efficient condenser or at least a larger one.

http://docs.lib.purdue.edu/cgi/viewc...&context=iracc

You might have to change to a parallel flow condenser to get it better. I don't know who makes one so it will have to be a "Universal Fit" one which usually means "Fits nothing in this universe without a lot of work and then, still maybe not.".

 

No, just much harder to find. I went to two shops and one said they had no equipment to work on R-12 systems. The second shop found an old manifold set and put in my two cans of R-12. They said everybody has converted to R-134a. They did say that there are shops for the "purists" with classic cars that insist on using R-12. They didn't tell me how to find these shops.

I bought an evaporator and condenser from a '94 Corvette (first year for R-134a) they are quite a bit thicker than the R-12 equivalents (like at least 50% thicker). I'm concerned about the condenser because in 1990 they started putting the radiator and condenser at an angle and the fittings are also angled. I haven't worked up the courage to bend the fittings yet...

 

People with a passion for older cars might form clubs. IDK. I have a couple shops that will do it around here, last time I checked.

I wonder if that will fit my 91. I might try that route if I ever had to replace a condenser and see if that helps since I have to replace it.

 

aklim - You are correct - "better" is subjective. I only know of a couple of people that have converted from R-12 to R-134 and I've only experienced one of those systems working - I personally could not tell the difference driving at highway speeds on a 90 or so degree day - but as I expect you know - good airflow over the condenser, a couple of thousand engine RPM and a 30 or so degree temp delta is not exactly "pushing" the OEM system (this was not in a Vette). I expect that if the OEM's were already starting to plan for the switch to R134 when the car with R-12 was manufactured, and had already started to upgrade components - that will make a big difference. This post refers to a car manufactured WELL before the eliminating R12 mandate was put out - so the results of the conversion may NOT be as good as if the car was made in say 1992.

The point of my post was to get the OP to do a little bit of diagnostic work to get to a point where a reasonable decision could be made. If the OP has a decent relationship with a local shop - and can get them to check existing system pressure quickly - that will help. If there is ANY kind of decent pressure in the system - it's probably not going to make sense to convert to R134. If the system has to be opened to do a repair - any licensed shop will have to recover the existing R12 - and as I'm sure you know - that recovery equipment is far from cheap - but that same equipment will happily put the R12 back into the system after the repair is completed. What I didn't say in my Original Post is that it's quite possible that with a early C4 - the repairs could easily start to get to the point where it's a significant percentage of the car - and then a decision has to be made about the economics of putting major money into that car....

As for R-12, for me - locally - it's almost not available, and Yes, I do have the card to buy it. Heck - the pricing on R22 for older home systems is now around $550 for the 25 Lb tanks (wish I had known that 3 years ago when those tanks were less than $200), and they are considerably "more available" in this area. R-134 on the other hand can currently be purchased by anyone (although I've heard there are some in DC that want to change that), and it runs about $5/small can, or around $100 and change for the big tank.

 

AFAIK, the relatively few conversions I did assist with, if the person didn't try to skimp on labor or parts, it did blow cooler air than ambient. Had a couple of friends that asked me to help with their conversion since I did it before and they tried to get some junkyard part, didn't test it or something and it had issues.

Correct. It is the 90 degree day that is hot and humid that "separates the men from the boys", so to speak.

I'd go with 94 since that is the first year they had it in C4s. What you say is really wishful thinking especially from the standpoint that we are talking about Government Motors. Remember Ford and the TFI recall? We don't change and squeeze the maximum out of the part until the suits cost more than what we will spend on the recall was the bottom line in 2002. Do you believe that GM that squandered it's home field advantage and lead would have been proactive and designed a stop gap that was better than a R12 system to last a few years? Design and testing costs money. They don't spend money till they are forced to. IIRC, it was in the mid 80s that some law came forth so they would have known since the late 70s that CFCs were going to be problematic.

Absolutely. A diagnostic have should be made BEFORE purchase but that is another story. We also have some shops around here that make sure you have either R12 or R134A or they refuse to work on it. Some make you responsible if you put crap in the system and their machine screws up because of it or so the waiver goes. Kinda why I don't use those "mechanic in a can with sealant".

 

Jeez, the OP is just looking for some guidance on how to fix his A/C

 

True but barring good luck, the gas might have to be evacuated is a real possibility

 

R134 AC systems built from scratch blow just as cold as R12 systems. However, R12 systems that are retrofitted to use R134 do indeed lose their efficiency at an idle especially since R134 is not as efficient and much less dense than R12. This is SoFlo! We know quite a bit about cooling since we run the AC all year round.

My friend is a licensed HVAC Technician. I wont say what knowledge I have simply because here you have to be licensed to work on Home AC units. We've used R434 Freon which is intended for home usage before in an R12 car AC system and it worked fine. There is a product called Freeze 12, which is a propane based replacement for R12 and works as good as R134 without retrofitting. Freeze 12 is not cheap but you dont have to do anything except fill the system. Yes, R12 is not only more difficult to get it is much more expensive than R134. Alot of times it's nearly triple the price for one stinking can of R12 and that's considering the price of R134 has gone up in recent years. The average can of R134 down here goes for about $10-$15 while a can of R12 is going for over $40 usually "off the back of a truck".

DSimon55, the first thing to try before doing anything else is make sure the compressor works. As barbaric as it may sound, this is quite easy. All you have to do is turn the AC on and unplug the low pressure switch which is connected on the bottle. Stick a paperclip in the plug and if the compressor kicks on, it's still working. Most likely you have a leak somewhere. If the compressor's clutch does not click, try it again a couple more times. If nothing, than your compressor is shot. At that point, it's up to you where you want to start but Aklim is right. The only way to really do it correctly is to replace everything with new parts and start with R134 from scatch.

However, if the compressor does kick on and you feel your car blowing cold air with the paperclip still in than replacing the low pressure switch on the bottle maybe all that you need to do. But considering how dense R12 is, chances are that the R12 has completely leaked out after so many years. Good luck buddy!

 

Absolutely. Except for the fact that you needed the SCOTUS to verify your state counts during the Bush vs Gore election. Since then, you counted apparently. Thank you, thank you. Don't forget to tip your waitstaff and I'll be here all week and yes, I still have my day job.

Agreed but the way I am looking at it, I fixed 2 compressors in my other car that was originally R134A. Not bad for 479K on the clock. Even at 3 times, you don't put that many pounds in, do you? Isn't it under 2 pounds? Say it costs $80 more and lasts 100K, it isn't that bad when you figure it cools better all day long and not just on highway speeds. Rest of the stuff, if you have to replace costs about the same, right?

For me, once the system is depressurized for any reason, a new receiver dryer will be put in. Cheap insurance. I also take the compressor out, pour out the oil and see if there are particles. IF not, dump fresh oil, circulate a bit, dump out and put fresh in as a rinse. In case of a compressor failure, I would think flushing the lines wouldn't be bad since you already have it apart.

PS. Anyone know if the 94 condenser will fit the 91 lines without any bending? I tried to bend something there once and broke the metal so I'd like to avoid it if possible should I try dump the condenser in it.