MitchW

I have a 2004 TT Cab with 29K miles on it. The motor has been noisy since I have owned it (since 14K miles), but the noise has gotten a bit more noticeable as of late. I have heard a u-tube video of a 2004TT making the same noise, and it was said it is likely the intermediate shaft but that it should not be a problem in a 2004 model year (corrected that year). I have also read that 5W-40 oil can reduce the noise. I have an MP3 file that I recorded with my phone, but this site will not let me upload and MP3. It is not too great, but I think gets the point across if anyone wants me to email it to them. Please let me know your opinions.
Thanks

BT ZR1

The engines on the 996 Turbo and Turbo S, use the motorcase of the Porsche GT-1. The turbos did not share this "intermediate shaft bearing" problem.

BioBanker

Does it tick in neutral?

Increasing frequency with rpm?

When you're in reverse?

fappds

normal sounds for these engines dont worry

SSST

Oil can help, but the ticking never completely goes away. It's normal. These engines are noisy. There is nothing you can do to make it sound like a Lexus.

PAULUNM

Could be a failure of the IMS itself. There's a key that backs out, noise gets a lot worse.

I'd switch oils, and inspect the oil filter for metal. If you see no or very little metal pieces (very small), you're likely OK.

John D II

The intermediate shaft is one of the weak points of this motor and is somewhat prone to failure. The bearings can wear or the woodruf keys that hold the sprocket on the shaft can round and get loose causing the gear to wobble. Although not real common, it has happened on a number of motors. I have heard of examples with as little as 25,000 miles and I think there have been some that failed at very low milage. When it does begin to fail, it will get a little louder. When it starts getting really worn, you will know something is very wrong, as it will get much louder and take on a character more like moderate hammering - to the point you will know it's just not right. If you think you have it that bad, have it listened to by a mechanic. A good tech should know when something is wrong. Unfortunately, this gives way to a few checks like chain tensioner failure, followed by removing and opening up the motor.

MitchW

I did a recent oil change and all was clear in terms of metal bits. I was reading through all the responses and feeling good until that last response. I'm thinking about having someone see it, although I'm afraid, as noted in the response, that it will lead to all kinds of unnecessary tests to see if something is wrong. The problem is I'm in a town where there are just not many of these cars, so I'm afraid the mechanics here will not know what is going on just by the sound. I anyone here familiar with Pat Williams of Pat Williams racing in Memphis? He has a shop here that does routine maintenance of 911's and probably has the most experience with these cars.

wross996tt

Just curious where do you get the data to suggest the IS is a weak point and "prone to failure"?

Macster

Noises are hard to derive any real meaning from unless the noises are so obviously from a sick engine that about all one can do is say that's one sick engine.

If you want private email me and I'll respond with my email address and you can send me the file and I'll see if I can listen to it and offer my layman's opinion.

Not sure how switching from a 0W-40 to a 5W-40 oil is going to help much. They both have the same viscosity when hot and the difference between 0w and 5w is slight coming into play at very low (the W means 32F) temps.

However, you can certainly move to a 5w-40 oil (I would of course strongly urge to you to stick with one of the Porsche approved oils.)

You can even use Mobil 1 5w-50 oil (not a typo for 15w-50) though I have used this oil in both of my Porsches (02 Boxster and 03 Turbo) and I can't tell from the engine sounds which oil is in the engine.

What I do notice is that after an oil/filter service the engine is quieter which arises from the fresh oil being more viscous. As the engine runs the oil becomes contaminated with unburned gas and water. Not all of this boils out and is removed with the crankcase fumes so as these liguids build up the oil becomes thinner.

Might add that I always change or have changed the oil/filter in my cars' engines at 5K miles.

Really, though, you need someone local to you and an expert on these cars and specifically the Turbo to listen and make some call.

IC reciprocating engines are noisy on a good day and to the inexperienced or simply someone with a bit of anxiety from reading/hearing about all the horrible things that can happen normal engine noises can sound like pending doom.

If you haven't already, join PCA and attend a get together. There I'm sure you will meet many Porsche owners and someone can possibly give the engine a listen -- all you have to do is ask -- and advise you.

Still, before you do anything to the engine you need a pro's input.

My WAG is the noise is normal but what I said about getting a tech's input still goes.

Oh, is the car a Tip or manual? If a manual what can happen -- my 03 Turbo exhibits this -- is when the car/engine/drivetrain are hot up to operating temp hot with the transmission in neutral and the clutch pedal released a light knocking sound comes from the engine area. I can make this noise go away for a while simply by depressing the clutch pedal then releasing it.

The noise comes from the clutch disc rattling a bit on the transmission input shaft splines or one or more gear sets in the tranny rattling. The noise can sound like it is coming from the engine and can be rather loud and appear to track engine rpms as long as the engine is left idling. However, if one listens long enough the noise has a come and go quality to it which is generally a sign the engine is not the source of a noise.

Sincerely,

Macster.

John D II

Hi William,

It's based on direct experience and from being involved with these cars for 10 years, nothing scientific - there are many reports of the intermediate shaft failing on the 996TT. I had it happen on my car, the woodruf key rounded causing the gear to wobble. I then learned that this has happened on many other cars. My motor had approx. 100,000 miles when this occurred and the entire motor internals were perfect and virtually "like new" with the exception of the IMS woodruf key. We did not have to replace a single part other than the IMS, but I chose to do all the bearings, all seals, the chain and chain tensioners. Based on this experience, I consider it a "weak design point" in the motor and since I learned of many others having had the same experience, I consider it "prone to failure". It's one of the few internal parts of the motor that "tend to fail". The motor is pretty stoudt, but this is a weak spot. I believe Porsche has done away with it in the new motors, probably for this reason.

SSST

If you are just talking about the light ticking noise at idle, then seriously, stop worrying. Every one of these cars does it to some degree. Type and age of oil can cause it to vary a bit, but unless the noise is getting worse or there is a new noise there is really nothing to worry about.

If you take it to a mechanic and tell them you think something is wrong, there is a good chance they will make it their business to find something wrong so you can feel good about yourself.

Macster's advice about finding some other owners to listen and compare to their cars is good. My wife is still not convinced that my car isn't defective, but I have learned I actually have one of the quieter tt's. I just had it in for its 60k service and the mechanic commented it was one of the quietest 996 tts he had heard. It's still the noisiest non-diesel vehicle I have owned.

Your car is to enjoy. Not stress over.

JG 996T

Post up the video.

MitchW

Here is the URL of the video...

http://www.renntech.org/forums/topic...shaft-failure/

Kevinmacd

Sounds normal to me!