Horror story about the A/C in my 87 Camry

copied from another newsgroup some time back:

The Toyota Technician Training Manual published by Toyota Motor Co. on Air Conditioning Systems, Course 750 lists several reasons why converting / retrofitting R12 systems to R134a is a major, expensive undertaking (if done properly).

Here are some quotes from the Manual:

1. "R134a attacks the nitrile butyl rubber found in R12 system hoses."

1. "R134a requires special carbon-filled iso-butyl rubber parts." (hoses and 0-ring seals used throughout the system)

2. "The conventional silical gel dessicant used for R12 may break down when exposed to R134a. R134a requires a molecular sieve type dessicant."

1. "R12 systems use a highly refined mineral oil lubricant. R134a systems use synthetic "PAG" lubricant which can cause swelling or foaming of conventional rubber gaskets and seals used in R12 systems. Be sure to special RBR rubber O-rings during assembly and repairs."

5, "R134a hoses not only have the special RRB rubber, but also have an impermeable inner lining of nylon to reduce seepage of the refrigerant and to prevent moisture entry into the system."

Now even if you spend all the time and money for these special hoses, O-rings, dessicant, etc., you still won't get the cold 37-42 degree F air coming out of your AC vents like you did with R12. You'll get more like 45-55 degree F air, which means the interior of your car will be about

10 degrees warmer on a hot day if you convert to R134a. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If your current shop has botched the job thus far, would suspect chances of getting them to properly reconstitute it now are slim to none.

------- I know this will hurt (financially) but would recommend you start fresh with a _qualified_ shop, explain the problem, and evaluate solutions now available.

------ The caliber of technician you're working with makes all the difference.

Did you have a written work order to this effect? If so, call the owner of the company and explain that the job was botched, and that you want to give them the opportunity to restore it to the original condition and then repair it per their work order.

If you don't have the work order in writing then you are pretty much SOL.

Either way, you're hurting. Since it looks like you need a new compressor, get one compatible with R-134a, replace the dryer, and the hoses. Converting back now will probably mean you still need a new compressor, and have you checked the price of R-12 lately? Do you have any Nitro pills handy? I could have bought a bottle of 30# two years ago for $80, it NOW sells for about $80 a LB!!!). So, right there, you're talking $180 JUST for R-12 (actually, I think the $80 is WHOLESALE!!!)

A compressor, either way, is about $275-325, the hoses won't be that bad. I tried a 'conversion kit' with an older Corolla; I have just given up on AC in that car. I only spent $670 about 6 years ago, when I could have converted it for that priced!!!

Unless the car is PRIMO (my Mom has an '86 w/83000 miles...) I wouldn't bother. Buy a '94 or newer if you can...it will alreaady have an R-134a system...

You've done good research. I've done several conversions some have worked well, some haven't. It depends on the age and design of the system. The compressor leaking/failing is not the shops fault; how they handle it is.

A month or so ago I did an inspection/ recharge of a 134 system; adding ac dye to see if there was a leak. the car left the shop OK but came back in last week, the ac inop. On the rack we saw the problem, (thanks to the dye) the condenser had failed and was leaking... BAD. The cost for a new condenser was around 600$ The customer didn't want to do this (I don't blame him) and we refunded all of his money for the original visit.

When I first started doing this auto work I read the stuff that said you had to replace almost every seal-hose-part because they were incompatible. I saw our shop doing the retro-fits by replacing the receiver dryer, adding pag and recharge. I was told this was how it was "Suppose to be done" I've seen retrofits that were a bit warmer than R-12, and seen them get colder than original. I've definitely seen systems that at least blew cool air where they didn't work when they came in; so, if you had nothing when you start...

My father-in-law bought the 30 dollar conversions at wall mart for his 89 astro. Realistically, all they do is change the r12 to r134a add the fittings. His AC worked quite good; so I asked a long time tech at work about this procedure and he told me that he has done hundreds of this basic conversions back east. Not the ideal way but it can and does work.

On my old Taurus I had the same dilemma. Old car, ac inop and had been opened. So I did a basic as retro-fit with no parts. Discovered the ac computer bad so I bypassed it, and the ac started blowing cool... Ok the basic system OK. Charged it up and blew out a line. 90 dollars to replace the receiver dryer and line and it worked ok for a few days, then quit. it has a leak I haven't found; but suspect the evaporator is leaking; cheap part but a bitch to get to. I might do one more check, but this ac system will probably stay dead.

If someone has a questionable AC system and has the knowledge to do it themselves; I would suggest the 30 dollar conversions at Wall Mart to start. This answers several questions. Does the Compressor work, does the AC system overall work, is there any major leaks? now if you find the compressor bad you can stop at 30 dollars.

i also did the $30 conversion (to R134) on my 89 ford truck.

same compressor, same hoses. works well after 4 years.

You've done good research. I've done several conversions some have worked well, some haven't. It depends on the age and design of the system. The compressor leaking/failing is not the shops fault; how they handle it is.

A month or so ago I did an inspection/ recharge of a 134 system; adding ac dye to see if there was a leak. the car left the shop OK but came back in last week, the ac inop. On the rack we saw the problem, (thanks to the dye) the condenser had failed and was leaking... BAD. The cost for a new condenser was around 600$ The customer didn't want to do this (I don't blame him) and we refunded all of his money for the original visit.

When I first started doing this auto work I read the stuff that said you had to replace almost every seal-hose-part because they were incompatible. I saw our shop doing the retro-fits by replacing the receiver dryer, adding pag and recharge. I was told this was how it was "Suppose to be done" I've seen retrofits that were a bit warmer than R-12, and seen them get colder than original. I've definitely seen systems that at least blew cool air where they didn't work when they came in; so, if you had nothing when you start...

My father-in-law bought the 30 dollar conversions at wall mart for his 89 astro. Realistically, all they do is change the r12 to r134a add the fittings. His AC worked quite good; so I asked a long time tech at work about this procedure and he told me that he has done hundreds of this basic conversions back east. Not the ideal way but it can and does work.

On my old Taurus I had the same dilemma. Old car, ac inop and had been opened. So I did a basic as retro-fit with no parts. Discovered the ac computer bad so I bypassed it, and the ac started blowing cool... Ok the basic system OK. Charged it up and blew out a line. 90 dollars to replace the receiver dryer and line and it worked ok for a few days, then quit. it has a leak I haven't found; but suspect the evaporator is leaking; cheap part but a bitch to get to. I might do one more check, but this ac system will probably stay dead.

If someone has a questionable AC system and has the knowledge to do it themselves; I would suggest the 30 dollar conversions at Wall Mart to start. This answers several questions. Does the Compressor work, does the AC system overall work, is there any major leaks? now if you find the compressor bad you can stop at 30 dollars.

A 20 year old system and you expect a guarantee? Find a used or rebuilt compressor change the receiver dryer and recharge.