Diagnosis for Whistling noise

[XfireZ51]

While driving Tuesday, I noticed a high pitched whistling noise during the times I was idling and/or sitting at a light. Did not change pitch with engine rpm and was not present when cruising. Closed throttle is when it is at its loudest. I pulled apart air horn/throttle body and spotted what I thought were telltale signs of an air leak on the gaskets. Installed new gaskets, buttoned every thing up and started car. Same whistle. Difficult to locate as it almost seems to be coming from everywhere. However it does appear to be more pronounced towards the front of the motor. Anybody else ever run into this. Car appears to idle and run fine. I still suspect a vacuum leak of some sort. :confused:

[Pete]

Sounds like a vacuum leak.
Had one thru the plenum gasket it sounded like a supercharger.

Pete

[tccrab]

Generally speaking, a leak big enough to hear will usually fubar the idle.
:confused:
However, maybe in this case it don't for some strange reason.

A really nifty "Grease Monkey - Old Timer Trick Quick and Dirty Vacuum Leak Test" is to use a portable propane bottle and spray UNLIT propane in the general area where the noise comes from while the car is idling. When the idle goes up, you've pinpointed your leak.

Good luck!!!

TomC
"Crabs"

[XfireZ51]

Sounds like a vacuum leak.
Had one thru the plenum gasket it sounded like a supercharger.

Pete

Pete,

Just spoke with Al. Certainly sounds that way. He suggested using a spray bottle and spray the gasket area. See if I can hear a "gurgling" sound.

Tom,

I used to use the propane bottle on my Xfire. Another notorious intake for vacuum leaks. Sometimes I feel like jumped from the frying pan and into the fire. :sign10:

[XfireZ51]

OK. Got it. Very unusual since this was a problem that was very easy fix. That's not supposed to happen with ZR-1s. Practically anything must require a "pulling of the plenum".
It was the release valve at the bottom of my "oil catch can".
It is now PLUGGED! :mrgreen::dancing

[GOLDCYLON]

OK. Got it. Very unusual since this was a problem that was very easy fix. That's not supposed to happen with ZR-1s. Practically anything must require a "pulling of the plenum".
It was the release valve at the bottom of my "oil catch can".
It is now PLUGGED! :mrgreen::dancing


I love the easy fixes. Nice catch Dom

[Pete]

OK. Got it.
It is now PLUGGED! :mrgreen::dancing



I like it when things get "PLUGGED" :thumbsup:


Pete

[secondchance]

:thumbsup: