HEPennyPacker

In the link below I posted a short video which captures the sounds my 996TT makes. It is a 2004 TT Cab - all stock. It has 24,700 miles on it.
In the video I wedged my iPhone under the rear wing to capture the sound as best as I could. I'm used to the chain rattling noise at idle and I've been told that it is a normal noise. What drives me nuts is a rattle or tapping sound that starts exactly at 2,000 RPM and up. When I push in the clutch and let the engine RPMs drop, the noise is still there until exactly 2,000 RPM and below when it can no longer be heard. The rattle is the same frequency as the engine and it makes the same noise with the clutch in or out.

Thank you very much in advance for your help!!

808Bill

Muffler bearings gone!

Flat6 Innovations

Sounds like the layshaft has a drive sprocket working loose. Check cam deviations. I see this one quite frequently.

You may also have a stretching timing chain, BUT I hear two noises, and one sounds like a rod knock. You need to have this checked out ASAP, and not operate the engine till you do this. No noise is a good noise and damage can be done just from trying to diagnose this by ear.

HEPennyPacker

Thanks, Jake. The tapping noise over 2,000 RPM has been there for a long time - at least a year, if not more. I only put a couple thousand miles per year on it. I'm not sure if that is useful information.

If you or anyone else has recommendations for a mechanic in the Columbus, Ohio area that would be great.

Thanks again.

Flat6 Innovations

Thats really sounding like the layshaft sprocket issue, then. The fact that it changes with the clutch in makes even more sense.

HEPennyPacker

it DOES NOT change with clutch in or out. The sound is the same regardless of clutch.

trendy996

I would take it to Wright Motorsports in cincinnati. I know its a hike but, thye're top notch. Search them

TonyTwoBags

Turbo forum also a great place to look for assistance

RngTrtl

i dont know wtf that is but as a 6t driver i would def take it in, something is for sure not right at all.

Macster

Noises are hard enough to diagnose when one is at the car.

My WAG is -- and I'll have to listen to this again at home where it is quiet the office is too noisy -- but it sounds like something outside of the engine. There are a ton a heat shields and a very tightly packaged exhaust system back there. Plus alot of other hardware.

There are the exhaust converters, too, one of which at least in my Boxster knocked about when cold -- I could have sworn the noise was excessive rod bearing clearance or crankshaft end play -- and buzzed when hot. Surprisingly the converter with the loose brick worked pretty darn good with just once in a great while triggering a P0430 error code.

Regardless of what it sounds like, what it proves to be, my advice is to get the car to a qualified shop for a professional diagnosis. The tech can quickly tell if the noise is coming from inside the engine or some other place.

I like to add best to flat bed the car to the shop rather than drive it.

However, I have to point out the noise has been present a while and that the engine hasn't manifested any signs of any serious issues strongly suggests the source of the noise is not internal to the engine or if it is it ain't that critical, at least so far.

Still, no need to press one's luck.

The professional will know what to do but if the noise is coming from inside the engine an oil drain into a *clean* pan and a check for any scary debris in the oil might be of some value. Likewise removing the oil filter and dumping it in another *clean* drain pan so one can look for any debris in the filter folds is probably a good idea.

I'd be tempted to get a suitable sample of the oil and send out for analysis.

Even before throwing a wrench on the car an experienced tech might check other things. Possibly cam timing (as has been previously suggested) and as best as he can whether the low/high lift feature is working properly.

These engines are expensive to open up and work on and one wants to be darn sure that level of work is called for.

HEPennyPacker

Thanks very much to everyone's feedback here. I'll take it in to my local independent guy for starters. The sound has been there for a long time - at least a year without getting worse. I had a pretty big shop do an oil change on it about 8 months ago and had Redline oil put in it. After that oil change all the noises went away for about 100 miles before returning. That shop thought that the noise might be a bad power steering pump and they referenced a technical service bulletin #41/05 and they recommended the pump be replaced. I don't see how that would be this noise however. Thanks again!!!

fpb111

See if it sounds like any of these?
https://rennlist.com/forums/996-turb...ine-noise.html