High Pitched Whine - Help Please

[hammerg26]

All,

I have a high pitched whine coming intermittently from the passenger side of the engine, near what appears to the evaporator. The truck is not currently malfunctioning in any way, so it makes it a little harder to troubleshoot. Also, when I turn on the defroster or A/C, the whine appears to go away. Any thoughts?

It sounds like it might be a vacuum leak, but I am not sure...

Thanks in advance.

Hammer

 

[wakeboarderNH]

How is the AC system working? Seem normal? It sounds kinda like the pully on the compressor, which you dont really just replace the pully you replace the whole compressor.
Check all the pully's and I'd check the belt and go from there.

Hope this helps

 

[hammerg26]

AC and defrost work fine, auto temp control works fine...
The really odd thing is that it seems to go AWAY when the A/C or defroster turns on... and none of the noise APPEARS to be at the front of the engine, it is only at the passenger firewall (for lack of a better location)...

Thoughts?

 

[wakeboarderNH]

Yeah I have no idea what something like that could be.
Thats really strange, I'll ask my teachers ( I go to UNOH for diesel ) and see what they think.

 

[hammerg26]

Any updates? The whine - actually more of a whistle, is still there... nothing seems to be "broken" (i.e. auto climate control works, defroster works, A/C - have not checked - is "cold" here for ATL)...

 

[toms89]

I would have the a/c system looked at. There are valves, orifice or whatever they are called where it converts it from high to low pressure. Since its related to the a/c being on or off that would be my guess. You may hear it equalizing the pressure as it is turned off. Someone who services a/c's may be able to give you an answer.

 

[Stabber]

Mine was doing the exact same thing and it was the PCV valve. Its very cheap and easy to change also