Porsche in WNC

Today it advanced from what has been a puff to 20 seconds of white smoke at startup. 2017 911S with 3500 miles. Service advisor had earlier said it was fuel burnoff associated with cold start and not to worry. This smoke is now excessive. Oil level is OK and has been. It seems the longer the car has been sitting, the more smoke at startup. Car had been sitting for 1 1/2 weeks before this morning.
I have a call in to the dealer/service advisor because what's happening is not normal or acceptable.
Any thoughts or comments?

Homeles

Doesn't sound good. Believe white smoke indicates water. Someone else more knowledgeable please chime in

dmtsc

Did you wash it before putting it up? If yes could be water sitting in tail pipes, will smoke like crazy until it evaporates.

LexVan

Could be normal after a 10-11 day sit rep.

Did you do a proper engine break in?

How did you drive it the time before the 20 seconds of white smoke? Short trip, long trip, easy or hard drive?

After a hard run, do you hear the electric water pump cooling the turbos?

Next time after a run, when you park for the day/night in your garage, let the car idle for about 30-60 seconds before shut down. This may help. The GT3 guy's report this helping.

I've never seen a puff of smoke from my car, even after a 6 month winter hibernation.

Some smoke. Some don't. Not uncommon on the flat six design.

LexVan

But it wouldn't start smoking immediately after startup if it was water or condensation in the exhaust. It would take a minute or so before the exhaust got hot enough to create steam.

STG

Is this a 2014-2015 GT3??

Have never heard of a 991 street Carrera ever smoking.

Macster

A brief bit of smoking at cold engine start can be normal if it is brief, the CEL remains off, and the engine doesn't manifest any untoward behavior: rough/erratic idle; for example.

The techs tell me they encounter this brief smoking at cold start all the time with used and even new cars on the dealer lot and the above is how the deal with the event.

In milder weather the smoke is indeed smoke, oil smoke. It comes from the AOS and its inability to prevent some oil vapor from passing through. This oil vapor enters the intake and because the heavier oil vapor particles can't make the sudden/sharp 90 degree turn impacts the intake wall opposite where the hose from the AOS connects to the intake. If the engine is shut off this oil warms up as the intake warms up from the heat soaking and the oil then drains down on top of the intake valves if the intake valves are closed, or runs into the combustion chamber/cylinder if the valves are open.

Upon a cold start, because the engine and exhaust is cold, the oil doesn't burn completely and a bit of smoking is what you see.

In colder weather the smoke can be accompanied by water vapor or because usually the oll smoking is infrequent the water vapor is all there is.

Oil smoke hangs together in even a breeze as it is carried away from the car. Water vapor dissipates even if there is no breeze.

Water vapor is normal too. It is a byproduct of combustion. When the engine/exhaust is hot unless it is very cold one doesn't see the water vapor.

Depending upon the ambient temperature and humidity the engine can emit visible water vapor for a few minutes or more.

Just a bit of some info FYI.

In the case of your car the smoking is as you suspect not normal by all I know and all the experience I have with this. (After over 310K miles in my Boxster and 3 replacement AOS's, 155K miles in my 996 Turbo, I've seen exhaust smoke and water vapor or a combination a good number of times.)

It is not fuel burning off.

There's not anything you can do about this other than note under what conditions the smoking occurs and relay this to the service department.

Be prepared to when you take the car in that you could get "they all do that". Ask for a demo of several cars. Before this comes up, if it comes up, look for a car that has clean (no rust) brakes. This suggests the car was driven a bit before it was parked and not too long ago.

Stress that the smoking has caused you to lose all enjoyment of the car because the smoking is not normal and you are concerned about the car suffering a breakdown and in this event jeopardizing your safety as a breakdown on a busy road/highway or freeway puts you at considerable risk.

You have to be prepared to leave the car. If the dealer can convince you to continue to drive the car this signals he can put you off.

So leave the car with it clearly understood -- wriite it on the work order if the SA doesn't and be sure it is on the copy the dealer keeps and the copy you keep -- the cause of the smoking must be determined and addressed to your satisfaction.

GTSMeister

No one so far going with a blown head gasket?

Homeles

That's what I was thinking, but didn't want to say it. It could also be water in the fuel.

Jabs1542

Wouldn't a blown heat gasket continue to blow smoker after start up? Particularly at high rpms?

GTSMeister

Depends on how bad. In a warm running engine any coolant leakage into the cylinders gets immediately flashed to steam and the amount is small so it would be hard to notice along with the other water vapor from combustion. Pressures are working against any inflow into the cylinder as well.

In a shut down engine, coolant leaks past the gasket into the cylinder for a long time since coolant pressure is high. That's what flashes into steam when you start up.

It also has a sweet smell, so that would be another clue as to the source. And over time your coolant level will go down very slowly.

If left un-repaired for a long time, coolant can score the cylinder bore.

911boy

White smoke is usually coolant from a leaking gasket.

reyesincc

I'm having to take in my 2017 991 for the same reason, heavy white smoke at start up after sitting for several days. Lasts for about 5 mins before it clears. What was the diagnosis from your service advisor and were they able to correct it?

Depan Patel

So I have 2017 911s got in July. 900 Miles. For the last 500 miles it is a huge cloud at start up after sitting maybe two days if have driven it like 30 miles plus. How did dealer fix it so I can tell them.
reyesincc, Porsche in WNC.
Please help what was the dealer fix?
503 702 7604

Porsche in WNC

I would take it to the dealer and explain what you have experienced. Per Porsche, the initial fix on my car was replacing check valves and oil lines feeding the turbos (required engine out.) Apparently did NOT fix the problem- still smokes (oil-white for about a minute) at startup especially after sitting for a few days. Car is now back at the dealer for a/the fix. They suspect bad turbo (seal-maybe?) Repair pending.
No fun/last straw.