Mongo

I came home from work today and noticed some odd sounds frkm the engine compartment:

1) When revving the motor, the engine sounds louder than normal. I am not sure if this has to do with my recent change back to factory cats and a resonance in the intake, or if the exhaust is leaking at the manifolds. I cannot hear any hissing under the car.

2) That squeaky sound is really annoying. I just put a belt on the air pump so maybe it is squeaky due to lack of use.

The youtube link to the video is below in case anyone wants to hear it. I hope I am just paranoid.

Mongo

It should also be noted that the installer did not use factory manifold to cat gaskets which leads me to believe that the incorrect gaskets were installed.

dr bob

Andy-- Do you have ramps or another way to get the car up a little bit while it's running? You can use your fingers carefully around the exhaust flanges to test for leaks. Or a short strip of cloth attached to something, watch for the leaking gasses to move the cloth as you go by.

If you suspect your new belt is squeeking, use a candle to lubricate it slightly. Just hold the candle stub against the sides of the V-belt for a few seconds. It will stop any squeeking for a while, helping you identify the source.

Mongo

Wow I will have to try the candle routine! I do have jackstands so I can start it up cold and quickly crawlbinder to check before it gets really hot.

Mongo

It is not an exhaust leak. I just checked and the pipes are fastened nice and tight. I want to say it is a flutter sound coming from the timing compartment but it could be resonating from the air pump. Can anyone hear a timing belt flutter in the vid? All my accessory belts are tight. Car has a Porkensioner by the way.

Mongo

As of this morning, with regard to the squeak, I rubbed the end of a candle on all of the belts too, but it did not get rid of the squeak. Still hard to tell where it's coming from, but I believe something may be rubbing causing it. I can't isolate it anywhere to the front of the motor.

Car is running great though so I'm guessing that resonating sound through out the engine compartment when I rev it may be from the air pump now that the belt has been attached. As I put my ear closer to the passenger front of the engine, it does sound like the growl is coming from there more than elsewhere in the motor.

I highly doubt my suspicion above about the timing belt fluttering. The PKT adjusts the belt tension so it wouldn't be possible for the belt to be flapping around behind the timing cover. There's no presence of heavy dusting coming up into the intake tubes from the timing cover holes, but there is a slight presence of dust which I believe is normal. The belt looks good when looking down through the inspection holes on the timing covers, tracking perfectly.

The Forgotten On

It is the air pump, I have to run one because of SMOG, but it is the only thing that squeaks in my 928.

One way to tell is to take the belt off that goes to it, if it stops the noise you are just going to have to live with it or remove the smog pump.

If it doesn't stop the noise, keep searching.