Garey Cooper

Like many people here my 996TT doesn't get driven every day and can sit more than a week between excursions.

I THINK the oil reservoirs in the turbos are draining dry in the interim periods....this is because right after a start up when the car has been sitting for a few days there is a loud rattling noise (really loud) that sounds coincidentally and suspiciously timed like the turbos rolling over. It completely fades in perhaps two seconds and reverts to the usual intermediate shaft rattles, etc.

Any thoughts out there in Turbo land?

Dock

Mine makes the same noise. My guess is it isn't the turbos, but rather internal to the engine.

WCE

Valvetrain noise, quiets down immediately when the oil pressure builds (which is pretty quick with oW Mobil 1). STILL, given the cost of these engines AND the known turbo cool down issues, it would have been nice if Porsche integrated an electric oil pump to prime the engine on startup and cool the turbos on shut down.
Oh well - planned obsolescence!

ltc

My car has been sitting for 12 months...don't ask, last time it was sitting for 16 months.

My mechanic recommends pulling the fuse for the fuel pump, cranking the car over until full oil pressure builds, do this a couple of times, replace the fuse, then start the car normally.

Just my 2 cents, wait, you've got change coming.

JP Schnitzer

Mine does the same thing...

ebaker

I think the cam chain tensioners leak down and the chain rattles for a few seconds.

tkerrmd

Guess my car is so loud with just the straight pipes I dont hear any engine noise??? Oh well, head in the sand again!!

99firehawk

its not your turbos they would have a hard time over coming graiuvty to drain down, The noise your hearing is normal, its the intermeadte shaft walking againts the front hosuinh, completely normal and no ill effects have ever been reported, Any 996 turbo you start up will make that noise

Garey Cooper

Hmmmm....thanks for the input all. I thought about the valve train noise as many cars will do this after sitting but this is pretty loud. And I've heard about the intermediate shaft and in fact the crankshaft walking.....

itc; I think your mechanic is giving you good advice there based upon all of this.

I had guessed the turbo's 'cause the sound seemed to be coming from about those nether regions and I had read that some of the turbo oil reservoirs had leaked in the past. But my car (knock wood) doesn't leak any life fluids.

So I guess the answer is; crank her over until she fires up, wait for the rattle to abate before any throttle at all.......keep doing this until you hear a really loud BANG! Then shut 'er down 'cause it done broke!

ltc

I especially like the part where they reuse the oil that's been drained out...

99firehawk

AS OF MAY 18TH 2000 cars recibved the updated parts, how many usa turbos are there with build dates prior to may 18th 2000

ltc

Just posted it since there was some question initially about lack of oil in the turbos.....it was addressed by PAG early on, that's all.