Engine sound

[redduck996]

With all my past and current vehicles, when I twist the key to turn off the engine, that is exactly what I get.. The engine shuts off. But with the p-car there's a second delay as the engine sounds like it's choking or hmm can't explain it.. It just doesn't sound like it's a clean engine shut off. DO you guys get this or is there something wrong with my p-car? COuld it be a weak battery?

[Loren]

My first thoughts are:

Bad gas (octane too low - knocking?) or a bad ignition switch...

[redduck996]

Loren,

No knocking and I never use anything under 93oct I'm going to trya bottle of that fuel cleaner on my next refill. It could be the ignition switch, let me try to turn the key all the way left the next time to see if I still get the idling ghost..

My first thoughts are:

Bad gas (octane too low - knocking?) or a bad ignition switch...

<{POST_SNAPBACK}>

[1999Porsche911]

Try shutting it off by disconnecting the negative battery cable. If the same condition exists, then it is not in the ectrical system.

[redduck996]

Just got my car back..All I can say is they did absolutely nothing..

First they said they tighten a few speaker screws on the right side (which was where the rattle was coming from) I still hear rattling from the door area.. It could be the passenger seat bc I do see it shake alot.

The driver side wind noise is still present. They said they adjusted the window by moving it up and out a smudge. I still hear drastic wind noise at 40-55 mph.. Not sure if thats normal or not

The rattling/clanking sound he said was from the flywheel which he said was absolutely normal. Odd thing was another c2 pulled into the garage area and as the guy shut off his engine, I didnt hear the noise I had.. So what should/can I do now, Turn up the radio and the noise will all go away?

What a waste of time taking it to the dealer..I thought they get paid for warranty work?

[1999Porsche911]

Tell him that the rattle from the flywheel is not normal and tell him to test it. That will mean pulling the tranny apart from the engine and testing the twist of the dual flywheel. If he refuses, go higher.

I would also confirm that it IS coming from that are by having them turn the car off when on the rack with you under the tranny listening.

[redduck996]

he said the fly\wheel is suppose to have play in it.. :(

[1999Porsche911]

Yes, he is correct that it should have play in it. Exactly 15 mm left and right and should return to center when released. However, it should NOT make any noise. A spring could be broken.

I still however, would not conclude it is the flywheel until you personally hear the noise coming from that area ofr the car. Jack it up and get under it and listen when someone turn the car off. You might be looking at the wrong thing.

[redduck996]

What will happen if no adjustments or fix is made? Is it bad for the car if I keep running it like this?

[1999Porsche911]

It depends what is making the noise. You have not yet told us whether or not you have identified where the noise is coming from. You have only stated the tech's opinion. Verify where the sound is coming from first. Noises can be like a tooth ache....you go to the dentist and tell him your lower right molar hurts and you find out it's the tooth on the other side of the mouth that is causing you the pain. Verify!

[cyclocross]

With all my past and current vehicles, when I twist the key to turn off the engine, that is exactly what I get.. The engine shuts off. But with the p-car there's a second delay as the engine sounds like it's choking or hmm can't explain it.. It just doesn't sound like it's a clean engine shut off. DO you guys get this or is there something wrong with my p-car? COuld it be a weak battery?

Hi, all. I have a 2002 C2 3.6L with maybe the same problem. It is a CPO car purchased in early February, 2006.

When I turn off the engine, as it spools to a stop, there is a rattling or clattering sound from the engine followed by a metallic screech just as it stops. At idle and above there are only normal engine sounds and no vibrations.

The rattle/clatter has been there for a couple of weeks, the screech is new. I didn't notice the noises earlier as they cannot be heard from inside the car, only in the garage when the windows are down or the door is opened (with all of the rain the windows have seldom been down).

At idle in neutral there is a rattling sound. However, when I press the clutch pedal the noise disappears. The service advisors at two different dealerships have said that it is the "throwout bearing" (my term) that is rattling. They say it cannot be adjusted and is nothing to worry about. Note that there are 44,000 miles on the original clutch and it is still smooth with no grabbing or slipping. So, I don't think it is the clutch.

The car has had a constant diet of Chevron Supreme, so I don't think bad gas is the problem.

The car is scheduled to go to the dealership next week. Any comments will be appreciated.

TIA

Dan

Edited April 12, 2006 by cyclocross

[nycebo]

Try holding the clutch in when you turn off the car and see if this resolves some of the clunk.

[cyclocross]

Try holding the clutch in when you turn off the car and see if this resolves some of the clunk.

Thanks for the tip nycebo. I've tried the various combinations are the noise persists. I'll see what the dealer has to say on tuesday.

[chance2001]

Just got my car back..All I can say is they did absolutely nothing..

First they said they tighten a few speaker screws on the right side (which was where the rattle was coming from) I still hear rattling from the door area.. It could be the passenger seat bc I do see it shake alot.

The driver side wind noise is still present. They said they adjusted the window by moving it up and out a smudge. I still hear drastic wind noise at 40-55 mph.. Not sure if thats normal or not

The rattling/clanking sound he said was from the flywheel which he said was absolutely normal. Odd thing was another c2 pulled into the garage area and as the guy shut off his engine, I didnt hear the noise I had.. So what should/can I do now, Turn up the radio and the noise will all go away?

What a waste of time taking it to the dealer..I thought they get paid for warranty work?

Man, can I sympathize with you. I had a 996 that had wind noise that sent me over the edge. After three trips to Porsche and multiple adjustments to the window angle etc., I took it upon myself to find the problem. I taped up my window with electical tape on the outside. The noise appeared to be coming from the driver's side window area. So after a roll of tape and many test drives, I was stunned to find it was the MIRROR. You see, noise travels and can easily fool you. The source may not be where is appears, or sounds, to be. After taping the miror up, the sound was gone. So I pealed off all the window tape and left the mirror tape on and no noise. I took the car back to the dealer and explained the situation and the took the mirror apart and rebuilt it. No more noise. Go figure.

Also, The metal sounds. Many factors can influence the sounds metal makes: heat (how hard you drive the car-rpms), speeds you drive it at and age. Here's why; the air cools metals around your engine and under the car pretty effeciently, but at lower speeds you'll find the metal can actually be hotter than higher speeds, depending on RPM's. I took my lazer thermal probe and read temperatures on my pipes and converter under the car after traveling across the DFW metroplex and it was much cooler than when driving hard around my neighborhood. The car reaches its maximum temperature AFTER you stop, not while you are driving. The metals continue to expand until they begin to cool and contract, and both processes create sound. Some cars are lounder than others. My buddies 997 sounds like a mouse compared to mine, but I drive at higher rpms per shift than he does and miine runs hotter. That's my story and I'm stickin' to it.

Good luck...