Hey Guys,

Just had the A/C re-charged today and the system appears to work quite well considering it hasn't had R12 in for 5 Years!

Just a little concerned that the Compressor Clutch isn't cycling correctly.

If I have the slide controls on Cold & Max, the clutch cycles quite regulary but any other settings - like Normal & Cold - well the compressor appears to run continuously.

What controls the clutch cutting on & off?

Is there a way to test for a possible problem?

Any help appreciated.

 

Pressure is what cycles the compressor, as the high side reaches it's set point, the pressure switch will clutch OUT the compressor, then when high pressure drops as it picks up the heat across the expansion valve going to the low side,,, the pressure switch will cut back IN the compressor to bring high side pressure back up. Sounds like it's running fine. Good to see that you used R-12 it's the best in our cars, nothing ELSE runs worth a crap in our cars except R-414B but shops don't use it, but you can get it.

The reason it runs more on normal is because on normal A/C your bringing in outside air which has heat that has to be taken out. When your on MAX it only uses the air inside the car. Personnaly I run on Max all the time and just turn the fan speed down, that way I don't bring in dust and smells from the outside world. The compressor doesn't car what setting your on, it only sees high pressure in weather it's low or high.

The pressure switch is located on the dryer or what you might call the BIG aluminum tank on the passagner side of the engine.

 

Hey Ryan,

Thanks for your reply, sounds like everything is normal then?

Just a little worried that the compressor might get tired early (bearing & shaft wear etc) with all that "running continuously" when set at Normal & Cold.

But what I didn't mention was that I was stationary on my drive when I was watching the compressor cutting in & out (Mainly on Max).

Maybe when I am driving around with the airflow coming through the car then the compressor may cycle a little more regulary to save on wear & tear?

Or maybe I am reading too much into this!

Whatever

(Hopefully!)

 

The compressor cycle time will be less when driving because it will be turned faster by higher rpms. Yes as long as it's cooling good don't worry about it. Your protected by the pressure switch so that if you ever drop below so many pounds of freon (as in a leak)it won't run the compress so that i won't damage it due to low freon oil.