Had some work done recently on my '03 ss. New upper and lower IM gaskets, new cooling fan assembly, new valve cover gaskets, new plastic elbows coming off of water pump, and trans rebuilt. Now I have this loud, rhythmic squealing (reminiscent of a belt squeal) that doesn't really change with rpm at all. It never happens right at start up, but if I give it gas or start driving, there it is.

This is important: The noise goes away when I remove the oil cap.

I have changed out the pcv valve, which is usually the culprit here given the symptoms and oil cap remedy. Still have the noise.

The shop even suggested it could be the torque converter, which the trans shop was willing to take it off and replace for free. Nope. Made the noise with no transmission attached.

It's rather maddening. Any 3.8 3800 owners ever have this same thing?

 

sounds to me like pressure built up in the crank case...check your pcv system...

since the noise disappears when you remove the oil fill cap...

 

Thanks for the reply STUMPMI. I changed out the PCV valve yesterday because they bent up the tip when the changed out the upper and lower IM gaskets. No luck.

It's obviously a vacuum issue judging from the oil cap removal creating a nice purring engine.

Can you advise of any other components that I could check?

 

Check the belt and all pullies/tensioners... hopefully it's something simple.

 

heres something to check:
Since you replaced the pcv valve yesterday....I would also check the actual hose that the pcv hooks to and make sure its not plugged...or pinched,kinked somewhere...Thats the pcvs job is to alleviate any crankcase pressure...and disapate any residual fumes in the motor...

The only other thing it could possibly be is either of the intake gaskets maybe sucking air! and when you pop the oil filler cap off it creates less of a vacuum effect....

I wouldnt recommend useing ether(starting fluid)...Maybe try a squirt bottle with water and spray it around the engine,valve cover etc and see if it effects the noise...or the running of the motor....

 

I dont think a belt or pulley would effect it when he removes the oil filler cap...and the noise disappears....IMO

 

I think I've pretty well ruled out the harmonic balancer, worn bearings on other pulley's, etc.

Everything I've found online about this noise says its almost always the pcv valve. The seals are great, the part is new...I can't think where else the vacuum leak is, unless they jacked one of the upper or lower gaskets when they replaced them.

Does anyone know if the EGR valve could cause this noise?

 

There is a o-ring for the MAP/PCV valve area. It sounds to me like that is missing. It's been known to sound like a failed alternator. The fact you can remove the oil cap and it goes away I believe supports that idea.

 

I had already replaced the PCV valve, so I thought I was up a creek in finding a solution. After I had made my last post I went out and took the MAP sensor off again and looked down into the PCV valve cradle. Sure enough, it looked just like it did when I snidely remarked that the repairman and bungled up the lower O-ring. It was contorted.

Ok, so after some self-humbling I took everything out and realized that the repair shop put the O-ring on the valve before inserting it, so that is what I did. That's wrong. You put the valve in its cradle, then the O-ring goes around it in a nice little recessed area...THEN the spring rests nicely on top of the O-ring. Then, the sensor goes on top as usual, no prob.

It's absolutely amazing. A very reputable shop and an equally reputable transmission shop were neither able to figure out what I was able to by using websites like this and others. I so appreciate y'all giving me your input. I was able to rule out any other major factors. Thanks a million.

My '03 SS purrs down the road again, and growls and hisses with the K&N FIPK just like it should, w/o nasty vacuum power draws.

 

Glad to hear you got it fixed!