I have a 2004 Dodge Grand Caravan. I noticed yesterday when I press the gas pedal a short burst of air releases. It sounds like an air compressor noise (when you fill your tires up and the air releases after removing the hose from your tire valve). The longer I sit in idle the louder I can hear the burst of air when pressing the gas pedal. After driving for a bit, I may or may not hear the burst of air. I can only hear it when the radio is not on. Anyone ever have this problem or know what it might be?

 

Welcome to DF
Have you just had the a/c serviced? Sound like the a/c system is overcharge and is leaking from the pressure relief valve.

 

You can unplug the compressor clutch to see if it is related to AC.

 

I haven't had to repair anything on this van except the relay for the heater. I will try the compressor clutch. Would it be related to the AC even if I wasn't using the AC or heater? I had everything turned off. That is probably why I noticed it.

 

The AC is on more than you think. Most cars kick the AC on when in defrost mode. The compressor can also cycle with the AC and defrost off as an anti-freeze countermeasure when refrigerant pressures are low.

 

The compressor doesn't run when everything is turned off, and it sure doesn't run when the pressures are low. That's the quickest way to compressor failure there is.

 

The compressor will run with defrost. I agree that cycling the compressor under low pressure is bad and I would be skeptical too. Until I had a problem with my old 91 T-Bird. The lines were disconnected and until I recharged it it cycled. I was told it was to keep moisture from freezing in the compressor. I feel stupid writing it because it doesn't make much sense but that's how it went down.

Edit: The more I think about it they may have been full of crap. It might have been cycling because it was low and the defrost was on at the same time.

 

If a compressor runs on a discharged system, something is seriously wrong. The freon in the system is what carries the oil through the system. The compressor would burn up in no time. That was the problem with the '01 to '03 Caravans, the design of the system was causing the compressors to be starved of oil and they were siezing up left and right. that's why they extended the a/c system warrenty on those. there is also a pressure switch in the system that should keep the compressor from engaging below 40 deg F. (or 40 psi system pressure)

 

Leak in the exhaust manifold maybe, I have seen the manifold bolts come loose before. That would give you that short spit of air.

 

Unless the manifold has a large crack, one or two loose bolt would leak when it is cold.