petes1966

A couple of times recently, my '07 997 TT has been really rattle-y when I first started it. First time this lasted for about a second, today for about 3 seconds. After that, it dropped back to normal, and the car ran fine. It sounded like a loose chain maybe, so I wondered if perhaps there was a sticky tensioner? Any ideas?

ta

pete S

jhbrennan

Ask in the turbo forum too - different engines.

flat666

could be normal tappet (valve lifter) noise. As the car sits oil slowly bleeds down from the tappets, and upon restart there is some noise as the pressure/wear compensation builds up again. It'll be especially noticeable if its cold out. also, jhbrennan is right. you should ask there too

pmt

I've been meaning to ask about this identical situation as it happens also to my 997.1 C4S, which has the 3.8 litre motor (about 12,000 miles on the car), under the same circumstances. Can get very loud, enough to draw the attention of neighbors, and not in a good way! I too would like to know the answer to this query. Thanks for asking, pete S.

StormRune

If you are referring to the loud exhaust sound in your case (without the metallic rattle that OP mentioned), then this is normal behavior when the car is cold. During initial warmup of a cold Porsche, the ECU makes the fuel mixture much richer than normal to heat up the catalytic converters much faster than they would otherwise - providing a net improvement in emissions. A side effect of this extra fuel is it causes a louder initial exhaust tone. If you wait for the idle to drop to its normal level before moving away (and you can easily tell by the reduction in sound that occurs in typically less than a minute), the car is much quieter when you drive away.