Reader Question: My 1991 Nissan NX 1600 has a new compressor, blows ice-cold air under 50 MPH. Over 50 MPH it blows warm air, slow down, it gets cold again or stopping, etc.
I have had it to 3 AC shops. No one has a clue. Do you have any idea?
Thank you so kindly.
Usually the opposite happens – Colder at high speeds and warm air at low speed or at stops.
First thing, which comes to mind here is either too much Freon in the system or there is a restriction in the AC system somewhere. It could be that the system is working TOO well, and it is freezing up.
I would triple check the Freon levels, and check the compressor Freon pressure at a fast idle speed. It could be that the compressor is never shutting off (it should cycle on and off and not run continually) and the system is freezing up.
I would check the clutch cycling switch and high pressure cut off switches as well.