r12 to r134a and new AC compressor

[mistaake]

The AC works in my 92 but I feel like it could be colder, the compressor really seems to drag on the engine, and the clutch likes to click on and off very rapidly. I'm hoping to get all the parts I need together and take it to the shop and have them overhaul the system, check for leaks, and do the conversion so that I can have good, efficient AC that I can recharge myself in the future if needbe. It looks like a Four Seasons brand "AC Kit" for about $200 on Rockauto gets me a new compressor with clutch, new orifice tube, and new accumulator. Any feedback on that brand - I've heard of it, but some good and some bad... Is there anything else I need besides the new fittings/adapters to make r134a hoses work? Also, I read that the condesnor should be changed too (then again those mainly referenced complete compressor failures that spewed metal through the system which is not my situation)... though on Rockauto they list different condensors for stock r12 applications and specific models (that are far more expensive) for r134a retrofit...

Thanks for any input, as I don't really understand AC systems.

 

[7echo]

This thread will have some AC information that should help, especially post 2...

http://www.gmt400.com/threads/new-ac-install.38384/

 

[Vjcamp]

I "retrofit" mine by recovering R12, replacing orifice tube, vacuuming and recharging system with R134a. I had to add a little oil so I used Ester Oil

 

[Sleeper Van]

The AC works in my 92 but I feel like it could be colder, the compressor really seems to drag on the engine, and the clutch likes to click on and off very rapidly. I'm hoping to get all the parts I need together and take it to the shop and have them overhaul the system, check for leaks, and do the conversion so that I can have good, efficient AC that I can recharge myself in the future if needbe. It looks like a Four Seasons brand "AC Kit" for about $200 on Rockauto gets me a new compressor with clutch, new orifice tube, and new accumulator. Any feedback on that brand - I've heard of it, but some good and some bad... Is there anything else I need besides the new fittings/adapters to make r134a hoses work? Also, I read that the condesnor should be changed too (then again those mainly referenced complete compressor failures that spewed metal through the system which is not my situation)... though on Rockauto they list different condensors for stock r12 applications and specific models (that are far more expensive) for r134a retrofit...

Thanks for any input, as I don't really understand AC systems.

Four Seasons is a very good product and has been around for as long as I can remember. As far as the Conversion goes don't forget that you have to completely flush the system and replace all seals and gasket's. The reason for this is the 134A uses pag oil. Make sure that the shop you go to will allow you to bring your own parts! It might be a little more money but you will have a guarantee if you let them supply the parts. It should be in the $750.00 range to change over. Don't skimp on the quality of the parts or the shop doing the work. You should have to work on it yourself in the future if it's done right. It should give you year's of trouble free service. Best of luck.

 

[Ken K]

R12 retrofit to R134a requires PAG oil with two type depending on compressor used. If you are using a R4 radial or V5 compressor, you need a heavier weight oil like ACDelco 15-100 PAG oil with a viscosity of 100. All other compressors (GM / Sanden / Diesel Kiki) use the new ACDelco 15-118 with a viscosity of 46. Use an inline metal filter with split brass compression rings on cone shaped rubber. These are sold by ACDelco and others. These are serviceable an capable of installing an orifice tube which should be installed close to the condenser to eliminate the glove box hissing noise when the system is shut off, then pressure equalizes. As for the condenser, because R143a carries less BTU's of heat energy, new condenser's use extruded aluminum tubing with 8 or 9 tiny rectangular passages per tube and are very skinny. This design transfer more latent heat up to 12 times better than the older "Tube" type condenser that looks like a small marble could go into one end and come out the other. Go the a salvage yard and look for a 98 or newer truck or van, then look at the shape of the tubes. They are clearly different and will help your system cool very well. As for the clutch cycling on & off quickly, indicates a low charge on the CCOT type systems as the low pressure switch at the accumulator to off when the suction side go low and on when pressure goes high. Keep in mind the low pressure switch is a different part number as the R12 would be about (24 psi = off / 38 psi = on), then with R143a, the switch changes to about (32 psi = off / 48 psi = on). Best of luck. Note; Use R12 oil on fittings to prevent frozen corroded seized fitting as PAG oil with draw moisture into the fitting.

 

[Steve A]

On the retrofits I've done, after flushing the system I have opened all the connections and replaced the o-rings with the HNBR type. Didn't want a leak on basically a new system. Like Vjcamp above, I used Ester oil in all mine as it's virtually impossible to get all the mineral oil out and PAG oil is incompatible with it. Manufacturers switched to R134a in the 1994 models so use that year model parts for compatibility and they fit right in your 92 model. Reduce the refrigerant charge by 10-15% from the R12 numbers. It's not that hard to do, just do a little research and twist some wrenches.

 

[mistaake]

Thanks all, I'm going to take it in and yeah I am pretty sure the shop will let me supply parts, since I work at the auto parts store and we deliver there anyway... just this way I pay employee price instead of shop price+markup LOL. Will be sure to supply condensor, gaskets, etc.