porschemikeandnancy

I am about to upgrade from a 993 to a 996 turbo. I've read that the turbo engine is a derivative of the 993 engine. Thus, it does not suffer from the dreaded "hand grenading" of a bad intermediate shaft bearing.

What I'm wondering is the 993 engines are known for weak valve seals. Does the 996 turbo suffer from the same problem?

Thanks

Kevin

Actually the 996TT does have a minor intermediate shaft issue. I have narrowed most of the problems to "02 X50 cars. A very good tech at the PPI will be able to spot a noisy shaft. You either have it or not. I have seen sellers install load exhaust systems to mask the problem. So be warned >> buyer beware.

The '04 and later engine case is reinforced and redesigned. The first case out of Spain had a few issues. All of these should be purged out of the system.

Valve train is great unless you buy a car with high type 2 over Revs.

DesignerGenes

Please describe this 'noisy shaft' sound. There is a guy ranting on Yahoo Answers that "virtually all 996 cars have it," and "the fix by Porsche only partially solved it; the 997 is when it was really fixed." I'm assuming the case reinforcement you're talking about is that fix.

I'm a bit confused as I've read that the engine case in the 996 Turbo is NOT the same as in the normally aspirated car, but is taken from the GT1.

Macster

My 03 has it and I dare say all 996 Turbos manifest the sound to some degree.

The intermediate shaft is gear driven from the crank -- partially or totally gear driven cams are popular in race engines and the Turbo engine is derived from a race engine -- and the gear drive is noisy and can rattle a bit from the rormal backlash present in the gear drive.

Chain cam drives -- such as are present in the non-turbo-charged 996 and 986 and new DFI engines -- are also noisy though the noise characteristics are different. To avoid even the cam chain noise some automakers resort to re-inforced rubber camshaft timing belts which are very quiet but have to be replaced periodically.

In my car's case, far and away the most noise -- and in either case it is not intolerable -- comes from the transmission input shaft I believe rattling the gears in the transmission when the transmission is hot and the transmission is in neutral.

I can depress the clutch pedal and the noise stops and most of the time does not come back until after I having driven some come to another stop and shift the transmission back into neutral.

I can barely hear what I suspect is some intermediate shaft gear rattle/noise but I'd rather hear that than the horrible noise of a failed IMS bearing that so many owners of the 996/986 engines have heard.

Sincerely,

Macster.

cannon1000

I have an '02 996TT/X50. It was inspected by Porsche Dealer (PPI) and an independent Porsche Shop. Would this be something they would normally observe and disclose? Would I need someone that was aware of this potential issue to look for it specifically. I don't like playing with hand grenades.

Macster

Not sure what you're asking or are after.

Generally unless the owner complains -- ran into a new 996 that the owner had returned to a dealer cause of too much engine noise which proved to be a bad lifter and was fixed under warranty -- or the engine exhibits other symptoms that might be related to the noise the car is not rejected because of engine noise. Internal combustion reciprocating engines are noisy even on a good day.

Give a couple of different Turbo engines a listen to build up a feel for what's normal and what might not be normal. Then give the engine in the car you're looking at a listen. Only you can judge whether the noise is within your comfort zone.

My car was CPO'd and still it a bit of noise. But nothing gruesome. As I mentioned the noise is not intrusive and I was aware before I bought the car the engine could manifest this noise to some degree. I listened carefully to the engine while it warmed up and after it was warmed up and the noise was not at all bad at any time and didn't get any worse when the engine was warmed up. Also, the noise was not rhythymic or periodic like a noisy lifter of something similar just a bit of noise at semi-randon beats/times that is typical of a highly tuned and high performance fuel injected dual overhead cam engine with its intermediate shaft gear driven and its cams driven by chains.

In your car's case, I assume that if the noise were bad enough someone might mention it. But maybe not. Depends. Depends if the noise falls into the what's acceptable or what's the typical range of noisiness, to the person doing the inspecting, listening.

Some engines are going to be quiet. Some a bit noisy, kind of in the middle. And some are going to be noisy, noisy enough to place them at the upper end of what's considered acceptable.

Added: Just might mention be careful you don't work yourself into a tizzy over a bit of normal noise. Anyone with any good hearing can tell you these engines (all modern Porsche engines) are noisy for various reasons. Most other carmakers' engines are similarly noisy. It is an inherent characteristic of these types of engines. Some automakers resort to rubber timing belts and engine sound covers, etc., to dampen the noise, but the noise is there.

For us Turbo owners the engine's right behind the driver's door. The engine cover is open which lets noise out. The intercooler air intakes can help to attenuate the noise. There is alot of engine, and engine accessories, exhaust, etc. crammed into a small space at the back of the car so there will be lots of sources of noise.

Sincerely,

Macster.

Kevin

On start up in the morning if you walk behind the center of your muffler and get on your knees there will be a death rattle between your tailpipes.

Who is running 5W40 or 5W50 oil?? USE IT..

Next, can you guys pull your own oil filter and cut the paper element open? You will see metal gradually increasing in the filter>> or do you trust your mechanic to look at each filter element?

Sometime you need to TAKE over your own service repairs or get involved in them directly.

PAULUNM

Kevin- I keep hearing that if the noise goes away when the motor is revved above 1k rpm, nothing to worry about.

Also- are you saying if you have an IMS issue, your filter element will show signs of metal?

Paul

Kevin

Does your noise disappear?

The noise will get worse. The IMS bearing wear is accelerated> the metal should get filtered.

The cure is a full engine rebuild.

PAULUNM

Yes, it disappears when reved above 1k or so. On startup, the noise is not really noticeable (if at all).

More noticeable at idle when the motor's been warmed up.

I've checked my filter element, but will continue to do so.

MechanicalEng

My engine also get louder when its idling warm, actually everytime I pull into my garage after driving the car it sounds similar to noisy lifters or very loud injectors... the car is quiet on cold startups...

Kevin

The noise off idle should quiet down with RPM input > smooth out.

If the engine gets louder when it get hotter, change to a 5W oil.

Pull your filter elements apart and look for metal from time to time

MechanicalEng

Kevin I mix 3QT of 15-50 with 6QT of 0-40 at every oil change (every 4k miles), is that advisable to do? I will check my filter next time I chage my oil...

Kevin

ME, if you are tracking your car, 4K is to far to stretch your oil change. I can see if you were to pop a new oil filter in at 2K.. With that said.. I can't win with this oil/ engine noise debate.. We see 13 post but I will receive 30 emails asking what I recommend. Received 14 already..

Guys go to your local NAPA or O'Reily's or XYZ and purchase a couple cases of Mobil 1 5W40 Turbo Diesel Truck and RUN it. If you want to inflict some pain purchase by mail 5W50.

Do NOT mix the weights unless you need a emergency top off. 5W is good to 22 degrees F.. And then we have lateral movement on that because we have a DRY SUMP located up high in the engine. HEAT rises..

Put another way.. DO NOT run 0W40 if you CARE for your engine internals. This falls inline with my 997SSK vs 997GT3 recommendation on the other thread.

Buy the Turbo and Diesel and be done with it. This oil does NOT have to comply with the EPA additive bans >yet..

mdkelly1

Good advice from Kevin. Changed to 5W-50 last time. Immediately noticed a reduction in start-up noise and in increased hot oil pressure at idle.

Also, there has been less oil consumption (basically none) with 5W-50. That was my experience anyway.