'96 Nissan Pickup Air Conditioning Question?
My Nissan pickup just started making an odd noise when the AC is running. It sounds like a quick burst of air being released, similar to disconnecting an air hose from a tire valve. It's somewhat random, but seems to happen more frequently the longer the AC is on. Sometimes it's a soft "poof", sometimes louder with a slight metallic ring to it. I still get cold air, but have the feeling that this is a warning that the system is about to fail. The truck is meticulously maintained and in otherwise excellent condition.
Any ideas?
I've opened the hood and run the AC hoping to find something, but it works just fine. Compressor cycles normally.
I probably need to drive it until the condition reappears, then pull over and look for something. It showed up originally on an 80 mile round trip and was occurring every couple of minutes by the time I got home. Unfortunately I was unable to check it out right away.
Update: It doesn't happen at idle speed, but if you bring the engine speed up to 2000 rpm's, it does it. It's definitely an AC problem. If you turn the blower on with the AC turned off, nothing happens, but with the AC on, as soon as you turn the blower on you get the "pffft". At least I now can replicate the problem and take it somewhere for diagnosis.