Carlo_Carrera

+1

"02996ttx50

It's fairly amusing for so many to say how "normal" it is when the car doesn't seem to exhibit the "noise" when new or even with low miles on it.

My last 996 turbo never once made this particular noise. So does this mean for "some" cars this is "normal"? or simply that those suggesting it is normal.. could they possibly have "limited" experience, in diagnosing from the internet, what is or isn't "normal"? lol.

Or, another possibility: is it only "normal" on aging Porsche 996 turbos? Pick one lol

Macster

Being I use my Turbo rather frequently (and the same goes for my Boxster) the car seldom sits more than a day or two unused. But if it sits longer the cold engine sounds different upon engine start.

The chain rattle -- more like chain being dragged across the chain guide -- is a normal sound for my Turbo engine if I let the car sit for longer than a couple of days. Also for the noise to appear not only do I have to let the car sit for several days the engine needs to be fully warmed up -- which it is 99.9% of the time -- when I park the car. And my experience is over the years the ambient temperature needs to be elevated. For my Turbo this is a summer time only noise.

We just went through a spell of hot weather and even so the noise didn't appear upon every cold start. The last time I started the engine it did not make the noise. I believe the reason is I just didn't let the car sit unused long enough. I last used the Turbo Thursday and I parked the car around 8:30pm Thursday evening after my 30 mile drive home from the office. When I went to start the engine Saturday around 11:30am I expected the noise -- had my iPad handy and video recorded the start up (but when I checked the recording only lasted 4 seconds before it stopped must have touched the screen and stopped the recording) -- but the noise didn't appear. This in spite of going through a 100F+ day Friday.

But the time before, when I started the engine Thursday morning for my drive to work and after not using the car since Sunday or Monday the chain noise was present.

If any owner has a Turbo that makes this noise he is certainly welcome to have a professional tech listen to the noise. Obviously the owner will have to be sure he knows how to reproduce the noise which probably means leaving the car at the shop parked for several days then having the tech handy for a cold start of the engine.

Absent a CEL, absent any untoward engine behavior after the start or at any other time my guess is the tech will just shrug and just say to drive the car more.

(Like smoking upon cold start I suspect the techs experience this chain rattle upon cold start of used and even new cars on the lot as these cars often go weeks between engine starts.)

Chain driven cam systems are noisy. They have the issue of the oil fed tensioner which can and does bleed down from lack of use over time -- days is my experience -- and upon engine start can take a moment to pressurize and take up the chain slack. For this reason a number of engine makers have opted for rubber timing belts to drive the cams. These are much quieter then chain cam drives but require periodic replacement. And while the cam drives are quite the owners are quite noisy and howl like the dickens when it comes time to have the belts replaced.

"02996ttx50

Great post as usual Macster!
My point was everyone keeps mentioning "normal" and I agree it only happens in intense ambient outdoor temps when the car has been allowed to sit for a few days..

But again, my previously owned lower mileage 996 turbo never once, exhibited that momentary yet piercing and highly disconcerting metal on metal "screech" and I had that car well over 1000 days lol . Certainly long enough to have replicated the conditions under which the sound which some of the contributors here are describing as "chain rattle and screech" and also as "normal". seems to me, it would have become apparent and manifest, under the same conditions. ( e.g. hi outdoor heat, and a car that has been sitting for a few days etc... ( dont do THAT!! drive it ) if this were in fact true, that it's "normal".

I would suggest it is a condition of wear, and only possibly "normal" as has been suggested as the car has been sufficiently driven and aged.

The cars don't make that sound when "new". So how is it now the "new normal"?.. and.. who'd like to venture an estimated guess as to at what point in the life of the cars motor, does this noise suddenly become... "normal"?! hah!

Berra

My car had 6k miles when it was in for that annual service I mentioned where the tech also checked for what I believe, was this particular noise.

Just drive

SeabrookPorsche

+1, I drive my car about once every 5 days and I get this exact noise.

Shadetree930

It is your Turbo's way of telling you that it needs to get out more often.

Carlo_Carrera

+1

Dock

^This

Charlie9

before you start it turn the key on and off just enough to turn the engine over a turn or two. do this a couple of times and it wont have the noise. It's the oil draining off the chain. It will also help reduce the wear on the chain guides.

Oak

pull the fp fuse located in C4 slot and turn the engine over till you see that the oil pressure has built up. plug in fuse and restart. no rattle.

Dock

What trigger do you use before you do this? That is, how many days without running the engine generates the fuse pull?

Oak

I generally pull the fuse everytime, my tt isn't a daily but I make it a good habit if it sits for a couple days. it takes more than a couple bumps to get the pressure built up. once you get in the habit of pulling the fuse you will be surprised at how much the starter needs to be cranked to build up pressure. that initial rattle is the sound of wear.

Dock

Thanks.

"02996ttx50

there is something so incredibly counter intuitive about the notion of pulling a fuse to *normally* start a car. the good news for me, is (a) its "winter" and therefore no oil starved screech at startup OR chain rattle. (b) now that i have replaced a new belt, there's a sometime momentary squeak to distract me from the other *normal* startup sounds.

the question for me is: do only *crazy* people only own these ? are do these particular cars make people *crazy*.