smoke on starting... aos or...?

[jeroen]

I know... been discussed at least a 1000 times already, and I've been reading up on it (yes, I used the search function), but still hoping to get some confirmation.

When starting my '97 2.5, I get the occasional puff of white smoke from the exhaust.
I know on an aircooled it's nothing to worry about.
Not so sure on the watercooled M96.

Mostly does it after short distance drives but recently it starts to get more frequent.

I removed the oil cap, but I don't notice any of the described symptoms there.
It came of like you'd normally expect and there doesn't seem to be much of a vacuum.

I admit replacing the AOS doesn't seem like a whole lotta work, but I'd rather not fix it if it ain't broke...

So, the main question remains:
Is it ok if I get the occasional puff of smoke when starting, or is it not supposed to do that at all...?

[ltusler]

Generally speaking a small puff on start up is not a problem. If you do not have vacuum at idle in the oil filler, your AOS is probably failing. If you are able, pull off you TB and have a look in the intake, if there is more than a film of oil in there, then I would clean it out and change the AOS.

[seningen]

Originally Posted by jeroen

I know... been discussed at least a 1000 times already, and I've been reading up on it (yes, I used the search function), but still hoping to get some confirmation.

When starting my '97 2.5, I get the occasional puff of white smoke from the exhaust.
I know on an aircooled it's nothing to worry about.
Not so sure on the watercooled M96.

Mostly does it after short distance drives but recently it starts to get more frequent.

I removed the oil cap, but I don't notice any of the described symptoms there.
It came of like you'd normally expect and there doesn't seem to be much of a vacuum.

I admit replacing the AOS doesn't seem like a whole lotta work, but I'd rather not fix it if it ain't broke...

So, the main question remains:
Is it ok if I get the occasional puff of smoke when starting, or is it not supposed to do that at all...?

This comes up fairly often....

It could mean virtually nothing -- or it could be a little more serious.

AOS is a possibility, but so is ovality issues.

Just like air-cooled engines -- oil can pool on the back side of the pistons
when car sits, then can seep through the rings after sitting.
It might be on shorter runs, the engine doesn't get hot enough and there
maybe clearance.

Unless you were going through a ton of oil or huge long smoke screens -- I wouldn't worry too much about it.

Mike

[jeroen]

Ok, thanks for the input.
For now, I'm gonna keep a close eye on it.
If I feel it gets worse, I'll just replace the AOS to be sure/safe.

[Steve Tinker]

As an aside, when I switched oils from Mobil 1 0W40 to a slightly heavier Shell Helix 5W40, I noticed a reduction in cold start puffs of oil.
Short engine runs also exacerbate the smoking when starting up the following day, so I keep that to a bare minimum.....

[thstone]

Occasional small cloud of white smoke on startup is normal. Nothing to worry about.

[Brad Roberts]

You know? You can call me right? Skype? FB me?

I owe you for all the work in the past!! at least you can let me help with the Boxster!!

Tell wife and kid I said "hello"

[Brad Roberts]

slightly heavier Shell Helix 5W40, I noticed a reduction in cold start puffs of oil

Bingo.

When Porsche recommended the oil for these cars? Mobil1? They were not owned by Exxon!! Exxon bought them and yanked a good chunk of additives out of the Mobil oil brand. Add up the mileage on these cars? ZERO reason to run the 0/40

I'm running 10/60 in all the race cars. We just warm them properly before the first session. ZERO issues. ZERO smoking.