General Jack

iTrader: (4)

I've had a lingering problem for a while now and just made a discovery. When warmed up, my car chirps and/or whistles like a tea kettle. Sounds kind of like belt slip actually, except it comes from the BACK of the motor. Regardless, I replaced the belt several times, didn't fix the whistle - chased down some other things to no avail, it was very frustrating.

Well, I just discovered that when I remove the big vacuum line on the back of the driver side valve cover, voila, the whistle stops.

So... my question is, how do I fix this? I assume I need to keep the vacuum line plugged or a mess will result... but the engine idles fine without it (highly modified and tuned motor). And I'm sick and tired of sounding like a '92 hyundai with belt slip. AIR system has been long removed btw.

shaun

i had that same problem on my 98 grand prix gtp it would sound just like a belt chirp but i took the belts off and cranked it up and it still did it then for some reason(dont remember)took off the oil cap when the car was started and it stoped.
the car had the stock pcv system and only had a few bolt ons so its not like the car was really moded.
i just drilled a tint hile in the oil fil neck right under the cap and it fixed it so you can do that or get an oil cap breather.
metco makes them and are about 45-50 bucks.

Steve Gunn

Vacuum leak? Get a stethescope and try to isolate it. Isn't there a gasket on the round section on the back of the manifold? Spray it down with some carb cleaner and listen for a change in idle speed to find a leak if you have one. Or maybe you have some kind of restriction in one of the PCV/vacuum lines like a kinked tube or hose? I wouldn't plug or vent anything. Good luck.

OUTLAWZ RACING

iTrader: (9)

Take the valve cover off and check that rubber seal in the hole also check that entire pcv line it may be broken somewhere. Becare if its stock lines they are plastic and become brittle.

Reaper SS

iTrader: (9)

Had the same problem a long time ago. Did you remove the fresh air hose off the throttle body that connected to the passenger side valve cover and block them off if so you are creating a vacuum in the crank case and its pulling in air through what ever seal it can causing the whistle.

Reconnect the breather line to the throttle body or air intake and it will solve the issue.

General Jack

iTrader: (4)

Thanks for the response guys.

04BlackSilverado

iTrader: (6)

I had the same Problem as the OP, and I read your thread a while back and you helped me fix mine as well.

Thanks again

Reaper SS

iTrader: (9)

No problem guys always willing to help.