1996 Nissan Sentra cooling

1996 NISSAN SENTRA

82,000 MILES • 4 CYL • FWD • AUTOMATIC

CARLZEOLI02

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Had a compressor clutch go bad. Replaced all on the AC system professionally but the evaporator and condensor. System cools great until Highway driving around 50 MPH plus when the cooling diminishes and then returns normal cooling when speeds get below. The system worked fine before the compressor was changed.When I run the RPM up in the driveway to simulate highway RPM it cools normal and the fans cycle off and on as well. None of my local AC guys can seem help me. Any switches you know of that should be replaced?

Aug 27, 2008 at 3:20 PM

2CARPRO JACK

CERTIFIED EXPERT
11,533 POSTS

Might be a little low on refrigerant, when the rpm's go up the pressures change and if there isnt enough in the system it will shut down.Or if there is too much or a restriction in the system it will shut down as well.

Aug 28, 2008 at 7:55 AM

CARLZEOLI02

MEMBER
2 POSTS

Had refrigerant checked a couple of times. Could the high pressure cut off switch be the problem? Does it shut the fans off or put them on when sensing high pressure? Does this car have a pressure sensor or therostatic switch that could be bad? If there is a restriction could it be in the condensor?Already put in two expansion valves and dryers. It's a pity because this system works great around town until I hit the interstate and no one here in Kansas City can help me. Can you reccommend anyone in KC to me?

Aug 28, 2008 at 11:17 AM

2CARPRO JACK

CERTIFIED EXPERT
11,533 POSTS

Need to know what the pressures are @ idle and at 2,500 rpm. Could eb the high pressure switch, might be the system has too much oil in it and is causing a high pressure situation when held at higher rpms. Need to hook up a testing light circuit to the power wire on the compressor and run it in the car to see if the comp is still getting power to it when the a/c isnt working, this will help narrow it down

Aug 29, 2008 at 7:40 AM