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Toyota Corolla GTS - R12 or R134A

SuperRA on Thu May 06, 2010 10:17 PM User is offline

Year: 1990
Make: Toyota
Model: Corolla GTS
Engine Size: 1.6L
Refrigerant Type: R12

Hello, I'm back for more hurtin. I've been here before when asking about converting my Jeep Cherokee to R134A and have bought a condenser from AMA. Unfortunately I haven't finished that project vehicle to the stage where I charge up the system and run it yet! Anyhow, I have my daily driver which has just recently run low on R12 such that the compressor will no longer kick on. I only believe this because I've diagnosed everything to find that the dual pressure switch is tripped and I figured it's about time the remaining R12 get low. A tire pressure gage shows no reading on the port but when valve is pressed there is still some pressure. So I'm deciding to use either R12 or R134A but want to evaluate both paths.

R12:
Is there a way to tell if there is sufficient amount of oil in the system? If so, I would like to add some R12 to get the system working again until I can easily overhaul it along with the engine in the future.

When doing the overhaul, what is suggested to be done? I was thinking of flushing each component and reinstalling.

What to replace? What kind of oil do I use? Accumulator/Drier is cheap enough to replace, does it need to be? Hoses?

R134A: Same overhaul as R12 but with 134A compatible parts.
When I did my jeep, it was suggested that I move to a parallel type condenser, will I have to do that again or will the stock one work?

Will the compressor need to be replaced? Are there compressor rebuilt parts/kits? Hoses? Different expansion valve?

Thank you

Edited: Thu May 06, 2010 at 10:18 PM by SuperRA

mk378 on Thu May 06, 2010 10:25 PM User is offline

You have a major leak if it has gone down this quickly. A system with a slow leak will quit cooling months or years before it gets to zero pressure and the switch trips. Don't just top off it's going to leak out again.

The Japanese cars with serpentine condensers and no electronic controls ought to convert well enough to use in most of the USA's climates. Find the leak first before taking anything apart.

Edited: Thu May 06, 2010 at 10:27 PM by mk378

SuperRA on Fri May 07, 2010 12:13 AM User is offline

Thanks for the reply! I'm in San Jose, CA. It gets to the 90-100s at the hottest

Quote
Originally posted by: mk378
You have a major leak if it has gone down this quickly. A system with a slow leak will quit cooling months or years before it gets to zero pressure and the switch trips. Don't just top off it's going to leak out again.

Well, i has been months since I last used it, probably 6-7mos ago. The last time I used it, there were times when the A/C would trip on and off rapidly (.5 sec cycles) so I thought that might be the low pressure switch turning on and off. Also, the switch isn't set to trip at zero, there's still some pressure in there. 33psi is when it switches off and 30psi is when it switches back on from what I can read in the manual.

If there is a leak, how do I go about finding it? My work has Inficon r134A detectors, will they work for R12? I guess I'll have to find that out. We also have vacuum pumps and gages, that should work yea? Leak down test?

Quote
The Japanese cars with serpentine condensers and no electronic controls ought to convert well enough to use in most of the USA's climates. Find the leak first before taking anything apart.,

Correct me if I'm wrong, but I believe my car does have electronic controls as everything is wired up to an "A/C Amplifier" which controls when to turn on and off the compressor depending on the inputs it gets from the evaporator, engine ECU, compressor temp, etc. If you mean electronic in some other way, then would you please explain?

Also, what's the opinion out there on which way to go once everything is fixed? R12 or R134A?


Edited: Fri May 07, 2010 at 12:15 AM by SuperRA

Cussboy on Fri May 07, 2010 6:16 AM User is offline

Once you find/fix the leak, I think it would be cost effective and performance effective to stay R-12. My '88 Mazda truck is still R-12. Then one doesn't need to worry about what do do about the R-12 mineral oil in the system, the type of hoses, whether the condenser is sized OK for a switchover, the fittings change, etc.

If the system doesn't leak, then the R-12 is a one-shot deal. And it's available legally, and demand has dropped off for it as the vehicles age and come off the road.

SuperRA on Mon May 10, 2010 2:08 PM User is offline

Ok, so the leak detectors I have access to won't work for r12. Is dye an option? Doesn't it usually come in refrigerant so when it goes in won't it leak out?

Well, I can do the total system leak down test so I'll cross my fingers and hope that it doesn't leak.

Voyager97 on Tue May 11, 2010 7:55 AM User is offlineView users profile

If you have a leak, some of the mineral oil will also come out of the system as it is carried around by the refrigerant.
Look and feel around the outside of the hoses/pipework, all joints and connections etc. If you find an oily residue, probably caked in dust, you have found a likely source of a leak.

-------------------------
Vic @ Pennine AutoChill

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