Engine Noise

[jporter]

I have a 2001 996 TT and I have started noticing a knocking noise from the engine. I stated to hear the noise reflecting off the walls in the garage and off cars parked on the side of the road as I passed them. Although I only recently noticed it, it could have always been there. The sound seems to come from both sides of the engine although it is normally louder on the right side. I hear it up to about 2500 rpm and then it either goes away or the other engine noises are louder. Increasing the speed of the engine does increase the rate of knocking.

My first guess was that it was the tappets. I changed the oil (Mobile 1 0W-40) and the noise remained.

The noise also sound like engine knock but I have had several fill-ups of 93 from different gas stations and the noise remains.

The following is a recording of the sound. The mic starts out behind the car and then I moved it to under the left side of the engine. I would appreciate any comments on whether the noise is normal or a sign of a potential problem.

pt1.wav

[pierre]

hmmm... Hard to tell and I don't want to scare you, but you should be careful. Check this thread and my story. It all started with a bad noise... Your issue might be totally different, but it's probably worth having the "intermediate shaft issue" in mind when having your car checked.

Good luck and let us know!

Edited September 22, 2010 by pierre

[jporter]

pierre, Thanks for the reply. I had seen your thread when I searched the site I was hoping mine was different and that someone might be able to tell from the sound file. The engine is the original and stock with 34K miles.

[pierre]

Based on your sound file, I really can't tell what it is. Maybe someone will, but in the meantime, maybe you should play it carefully. BTW, the 'screw-into-chain'-issue can happen to any 996 or 997 Turbo, regardless of mileage. It actually happened to Sportec when they were road-testing an almost brand new car a few years back.

Go to your preferred mechanics and have 'em check your car!...

[jporter]

pierre,

Thanks again. I had the Master Mechanic at a Porsche dealer listen to it when I picked up the filter and washers for the oil change. He thought it was normal. This was prior to a DE at Mid-Ohio so I took the car to Mid-Ohio without any problems. I also usually, not always, get the rattle/clatter sound (tappets) for less than a second at startup that I used to get with my Boxster. Is it common to have some tappet noise when the engines are running at low rpm?

I will also take it to the other Porsche shop in town and see what they say.

Incidentally the car is very fast down the back straight at Mid-Ohio and I can only imagine how fast your car is.

[RFM]

It does any harm if you go for a second opinion, anyway, Turbo and GT3 engines produce more timing related noises than Carrera M96-97 engines.

[wvicary]

I don't hear anything to worry about. These engines do make above average noise particularly at idle. Monitor it to see if it worsens with use.