ffierling

My S engine vibrates a lot between 3000 and 4000 rpm with a strong peak at 3200 rpm. Above and below this range it's as smooth as a piston engine can be. It's most noticeable in second and third gear, but also evident in neutral - so it doesn't seem to be a problem with the transmission. Has anyone else noticed this and had it fixed? Could a problem with the dual-mass flywheel cause this symptom?

BrianPA

I don't want to scare you too much and my expirience does not directly relate but that same symtom turned out to be bearings in a different car. That means new motor. Better have it checked.

Tool Pants

Let's see if we can rule out the transmission and flywheel over the internet.

Been a long day for me. How do you get the vibration in neutral when the engine is at the 3k-4k range. Are you coasting in neutral with the engine reved up. Are you sitting still. What are you doing with the car when you are in 2nd and 3rd.

Rob

edited... sorry, wrong forum.

ffierling

It vibrates with the transmission in neutral and the clutch engaged or with the clutch disengaged, sitting still or coasting. It's most noticeable though when in gear, accelerating or decelerating. It seems to be worse when the engine's cold, but barely so.

More clues: The car is 6 months old, 13,000km. I've noticed right from the start that the engine doesn't pull smoothly through 3200 rpm at partial throttle. I assumed this was a peculiarity of variable valve timing. The vibration hasn't changed much in the last 5,000km.

I babied it through break in, but no more. If it were a crankshaft journal it would get worse fast - wouldn't it?

Thanks,

Tool Pants

Since you have a warranty take it in. Also see if you can drive the identical car and if it is different.

My friend had a rebuilt engine put in in July after 4 seal replacments. The rebuilt engine had a vibration between 2,500 and 3,000 rpm. He took it back and the first mechanic said it was normal, but his original engine did not do that. Took it in again and a second mechanic pulled the oil filter and it was loaded with metal - so the rebuilt engine did something to a bearing.

So, after 800 miles they put in another rebuilt engine. Same vibration. They thought this time it was the VarioCam solenoid. Replace it - same vibration. Then they wired the DME directly to turn on the VarioCam - no difference.

So, now he has a brand new engine.

He has a 2000 since new so he knew there was something wrong with the 2 rebuilt engines. Since you say your car has done this from new is why I suggest you drive another car.

ffierling

No, I said I noticed that the engine doesn't pull smoothly through 3200 right from the start. The vibration is relatively new.

I've taken it into the dealer and they claim it's normal. I'm going to check the oil filter and try some other cars as you suggest, but I still find it hard to believe that a horizontally opposed six would vibrate so much.

PTEC

So basically you're saying it happens any time you hit those RPM's?

Something is definately not right, that is not a normal characteristic of the car. Take it back to the dealership and request a ride with the shop foreman or the service manager. If they continue to say that its normal request a ride in a similar car.

ffierling

Okay, I've taken it to the dealer. First a mechanic test drove it. He thought it didn't sound right, but when he connected it up to his analyzer, the ECU reported no problems. I came back when the head mechanic was available and he acknowledged the noise, but said it was normal. He says he has swapped out clutches, transmissions and engines in futile attempts to eliminate it.

I have exchanged cars with a friend who has a 2000 Boxster S and he thinks it's abnormal. I could not hear the noise in his car, which has clocked only 5,000 more km than mine.

The casual driver could easily miss it because of the narrow rpm range in which it appears. However if you to shift into a higher gear such that the engine drops to 3200 rpm the whole back of the car emits an unmistakeable thrum. It is also possible to thrum under heavy braking with the clutch engaged.

I notice that this noise occurs around where the vario-cam is changing to a higher valve lift. Could it cause these symptoms?

ffierling

The dealer replaced the dual-mass flywheel: the vibration is gone!