I have a 1989 240SX, production date 9/89, with an ac problem.When I use my ac it will shut off after about 5 minutes ( I'm pretty sure it's the compressor clicking off ) The compressor and dryer are new and the system has been switched to R134a. This problem was there before the compressor and dryer were changed. The car has 200,000 miles on it. It seems like the hotter the weather, the shorter amount of time the ac will work. i can only get the ac to work when the engine is cold, once I get the ac to work one timeand it shuts off, It will almost never come back on again. I live in the Los Angeles area.
Please help , ThanksNeal00
Intermitent Air Conditioning
It sounds like there's a pressure switch that's turning the compressor off...the working pressures of R-12 and R-134a are different. Some systems have a pressure sensor to ensure that the pressure is within some given range. The difference in refrigerant pressure is making the car think something's wrong. Did the problem occur soon after the conversion?
Sorry I can't be of more help. Do you by any chance have access to a service manual with a wiring diagram? The best thing to do is to find the compressor on the wiring diagram and trace it back to find what relay, switches and/or sensors have any input to turning the compressor on. You might be able to cheat a little and force the compressor to turn on. When you did the AC conversion, what work was done? Just a refrigerant change, or did you have a complete flush with new seals, drier, and lube? Before the conversion, were you sure you had enough freon in the system?
When doing a r12 to r134 the r134 has different properties and it has been nec. to put .3 to .5 of a lb. less of r134 in a r12 unit to get it to cool properly do to a smaller capacity condenser. There is a brass sensor on the compressor and if you had to switch this sensor from the old compressor to the new this could be your problem. This is a thermal sensor and it cuts the grd. for the a/c clutch when the compressor gets to hot.