innovator

Hello gentlemen.

I just picked up a 2002 996tt with 10,000 miles on it. I traded in my 2003 Audi RS6. All seems well, except that after warmed up, I hear a rattle coming from underneath the engine. I am an Audi tech, and I hear noises all the time, but this has me a little nervous. I know these engines aren't silent, but it seems a little loud to be normal? I may have been a little to over-zealous when I picked up the car, and overlooked it...

I read about the IMS shaft issues, and the only way I can describe this noise is like a rat,rat,rat,rat.... Seems to get worse when the engine is hot, but diminishes when the engine is reved over 1000 rpm. Depressing the clutch makes no difference.

Thank-you Rick

Philip P

I believe the IMS is not a problem in the twin turbo motors

innovator

I did read the turbo does not suffer from the IMS issue. So then, is the rattle normal on a six speed turbo at idle ?? This is my first 996 and I'm unsure what is normal and what is not. If it were an Audi , it definitely would not be normal.



Rick

Dharn55

The TT has the old case design from the air cooled era. The IMS design is completely different and the IMS bearings are pressure fed and the design is much less prone to the IMS failures experienced with the M96/97 series engines.

Macster

What others have said. I can add the IMS in the Turbo can make a bit of noise, well, not the shaft per se but the gear drive. (Gear drives can be noisy which is why most passenger cars have switched to chain drives for this or even rubber timing belts.)

But this noise is very very seldom a sign of anything wrong.

Now in some cases my 03 Turbo will make a noise like I think you describe and this is the clutch or transmission input shaft/gears rattling about a bit.

My Turbo only does this after everything is warmed up and I bring the car to a stop concurrent with shifting the tranmission into neutral and releasing the clutch pedal.

I hear this noise and if I then fully depress and release the clutch pedal the noise goes away or greatly and I mean greatly diminishes.

How fresh is the oil in the engine? Does the engine have the right oil in it?

If you do not know or are not sure or even if you want to 'try' something you can have the oil changed and switch to say Mobil 1 5w-50 oil. (This is not a typo for 15w-50 oil!). Mobil 1 5w-50 oil is a Porsche approved oil and of course its high temp viscosity is a bit higher (50 vs. 40) than for say Mobil 1 0w-40 oil.

I've been using Mobil 1 5w-50 oil in my Turbo now for a while. (Which I might add I bought used in 09 with around 10K miles on the car and since then have added almost 60K miles.)

And this next oil change I'll run this same oil in my 02 Boxster -- which has just covered 245K miles the last 5K miles running Mobil 1 0w-40 oil without leaking, blowing up or making any scary noises, or ....uh sorry, where was I?

Oh yeah, anyhow, I buy Mobil 1 5w-50 oil at the local (and for me nearby) Mobil oil distributor here in Hayward CA. I just bought three 6 quart cases for $142.11 which works out to $7.89/quart which is far cheaper than the nearly $10/quart [added: for Mobil 1 0w-40 oil] I paid just a month or so back when my Boxster needed its oil level topped up with about a half quart of oil.

(18 quarts because not only is the Boxster due for its 5K mile oil/filter service the Turbo is just hundreds of miles from being due for its 5K mile oil/filter service.)

Anyhow, before you get all wound up over probably nothing at least considering changing the oil/filter and using Mobil 1 5w-50 oil. But even if the oil has just alot of miles on it, or especially if the oil is the wrong oil, simply changing the oil and using an approved 5w-40 (Mobil 1 or some other approved brand of oil) or even Mobil 1 0w-40 oil would be a good first step.

Or if the oil's fresh and the right oil then see if you can get someone with a bit more experience with these cars and their engines a chance to give the engine a listen. They can be a bit noisy (see comment above about chain drives...) and because they are a bit of beast, a bit more raw an engine than most other passenger car engines.

Sincerely,

Macster.

innovator

Thank you for the reply. I will change the oil tomorrow.

It does sound like gear rattle. I feel silly posting about this, because I own a repair shop and oughta know what it is, but we seldom do engine work on newer Porsches. I dont work on enough of them to know what they should sound like Only suspension , alignments and general maintenance.

Gaspasser19

Sounds like mine did each time a catalytic converter failed.

Macster

Don't feel silly. You didn't know, weren't sure, so you sought out some help. I am not an expert or professional though, so feel free to read what others have to say.

I believe though that if your Turbo engine were truely sick I think'd you know it from the noise.

I mean a sick engine sounds like a sick engine practically no matter the make.

I'm sure you are aware of this, but if the noise isn't affected by the clutch thing I mentioned in my first post, you can start the engine and with the noise present lift the car in the air and with a mechanic's stethescope give a listen to the engine and pinpoint where the noise is coming from.

Knowing from where the noise is coming from can only help you and the rest of us to better know what's going on, if anything is going on.

About that oil change...

Be sure you have a good DIY handy to refer to. If you can't find a good DIY online then PM me and I'll copy the section from the factory manual in PDF form and email you a copy.

Changing the oil/filter in these cars can be a bit tricky. You want to drain the oil from the crankcase and from the oil tank. The oil tank drain removal needs to be countered by holding the tank hex with a wrench to avoid twisting the tank when loosening/tightening the tank drain plug.

New drain plug sealing rings should be used.

The Turbo oil collectors should be drained though many don't do this. I do not know the reason why these should be drained though one tech told me to ensure that they both drain the same amount oil.

I note too both are located very low in the engine oil system and this could result in these collecting a bit of water or other stuff that a drain could remove.

Add the oil to the tank slowly and wait a bit of time afterwards before starting the engine to give some of the oil time to flow into the crankcase.

Do not overfill the engine with oil. The instructions call for the oil to be 70 or 80C hot and the car level and a drain time of 20 minutes. Then 7.8l of oil is added to the engine tank. The oil level is checked and the oil level should have the 7 lower bars/segments of the oil display lit, which puts the oil level at the max line.

This of course not only gives one a chance to change the oil but to also verify the electronic oil level sensor/display is working properly.

Sincerely,

Macster.

innovator

On my way to my shop to do just that

innovator

Just put it up on the lift. The noise is definitely emanating from the front of the engine. Toward the rear the rattle is much lower. It goes away completely when revved over 1200 rpm

I did find a bad front end link but otherwise this car looks like new. Literally. Take a look.

http://modules04.dealercarsearch.com...spx?id=1145763

Marc Gelefsky

+ 1 , I had that rattle when my Cat went south.

Welcome to Rennlist Rick!

innovator

Thank-you Marc.

It's a pleasure to now be part of the Porsche community

Paseb

wow , collector car, so gorgeous

now, you just have to get your rennlist membership

innovator

Got it

innovator

Thank you for the detailed reply. I have a few cases of Castrol Syntec 5w-50 with my cars name on it.