I have a 84 300DT with 140K. I just put on a rebuilt compressor, new expansion valve, new drier, new orings, and flushed the system prior to refill with R12.

Question: Why does my compressor run all the time when in AC mode? Isn't it supposed to cycle on and off? It gets nice and cold but I do not care to burn it up. Do all of the compressors make some noise? At idle, it sounds a little clunky but has not changed in about 500 miles since I repaired the system.

The temperature control seems to work just fine and it is consistant. I appreciate your advise. This is the first 300DT that I have owned.

Thanks,
MDE