White smoke from exhaust on cold start... - BMW Forum

d3ity · 10-05-2007, 11:39 AM

I hate white smoke.

There isn't alot of it... not even enough to really notice since it's been cold out for the past week...

This morning it was around 68*F, and I started my car up and noticed a little tiny bit of white smoke coming out of the exhaust. Now I'm pretty sure I've got an exhaust leak anyway since I can hear a hiss when I floor the car.

Could this be just a bad o2 sensor or something to do with the fact that my car could use new spark plugs and a tune up in general? Or is this an indication that I need to get rid of this car now before thousands in repairs start showing up. What should I check for?

Torque · 10-05-2007, 11:42 AM

Water condensation evaporating as the exhaust heats up?

d3ity · 10-05-2007, 12:06 PM

Sounds plausible, since the problem goes away after like 15 minutes of driving... and it isn't bad at all. I'm not using any coolant and I know I have a pinhole leak in my oil pan...

And given the exhaust leak... probably just condensation.

bow · 10-05-2007, 03:56 PM

oil over fill?

kol2upt3d · 10-05-2007, 04:27 PM

White smoke on startup can sometimes mean a leaky head gasket... causing coolant to seep into the cylinders, the smoke is actually steam.

Have your head checked

Torque · 10-05-2007, 05:35 PM

Quote:

Originally Posted by kol2upt3d

White smoke on startup can sometimes mean a leaky head gasket... causing coolant to seep into the cylinders, the smoke is actually steam.

Have your head checked

He said he doesn't have any coolant loss ... I'm sure there would be some if the car is smoking for 15 minutes on a cold start.

As for the other post, oil produces a light blue smoke ... plus it smells like ... burnt oil.

I still think you're overreacting and it's just water evaporating, but take it to a shop just in case if you're skeptical and have them reproduce the symptoms and tell you.

kol2upt3d · 10-06-2007, 12:19 AM

Quote:

Originally Posted by Torque

He said he doesn't have any coolant loss ... I'm sure there would be some if the car is smoking for 15 minutes on a cold start.

As for the other post, oil produces a light blue smoke ... plus it smells like ... burnt oil.

I still think you're overreacting and it's just water evaporating, but take it to a shop just in case if you're skeptical and have them reproduce the symptoms and tell you.

What he said

d3ity · 10-06-2007, 10:33 AM

My coolant level sensor is actually shot anyway, so it reports coolant level all the time. However, I check it usually once a week and haven't noticed anything major.... or minor for the matter. I'm pretty sure i'm overreacting. it's been rather humid latley and it's been foggy out for the past two days.

As for oil being overfilled... I've got a leak in my oilpan... so I doubt it's that. However, if I open the oil fill cap while the car is running, I do have some smoke coming out in puffs there... I've been blaming that on my valve cover gasket needing replacement.

CosmosBlack · 10-10-2007, 05:29 PM

I had to check to see if I wasn't on the Porshe forums!
That is something you'd get from a flat 6 Porsche engine.

I have white/blueish smoke on startups, that goes away in a few seconds.
No smoke on hard acceleration or at anytime after that, until the next startup if it sits for a while.

Do you get the smoke when moving also, or just at startups?
If there is smoke consistently, one possible cause could be a bad oil separator.

d3ity · 10-10-2007, 05:45 PM

Just startup... occasionally.

Not that it occours while driving (at least, after the first minute or three), but when the car is started cold it does throw out some smoke... which I believe is just steam.

Torque · 10-10-2007, 07:23 PM

Quote:

Originally Posted by d3ity

My coolant level sensor is actually shot anyway, so it reports coolant level all the time. However, I check it usually once a week and haven't noticed anything major.... or minor for the matter. I'm pretty sure i'm overreacting. it's been rather humid latley and it's been foggy out for the past two days.

As for oil being overfilled... I've got a leak in my oilpan... so I doubt it's that. However, if I open the oil fill cap while the car is running, I do have some smoke coming out in puffs there... I've been blaming that on my valve cover gasket needing replacement.

Well yes, since it's hot in there ...

OWarrior · 10-12-2007, 07:28 PM

check your engine oil, if its at a proper Guage, then u're fine. if its short, your Exust recirculation valve is bad. it happened to me in My E39 525 (sold off now)

d3ity · 10-12-2007, 09:00 PM

I assumed so... but... meh.

benzin · 10-20-2007, 12:21 AM

Could be a bad valve seal.As the car sits it leakes in to the cylinder.Pull some plugs and check for oil.You could allso do a pressure check,That would rule out a bad head gasket.If it is a bad valve seal its not that hard to do.Provided your are machanicly inclind.A head gasket is a little more work,But again not that bad.

chris528 · 02-13-2008, 01:22 PM

I'm new here. I came to see if there was any info on a similar problem i've been having with my 97 528i. I've been told that it's a problem with the crankcase vent valve building up moisture and sticking. In my case I'm from northern Minnesota and mine freezes solid. BMW has recently issued a repair bulletin including replacement parts to include insulated crankcase valve, insulated hoses, and a new dip stick tube witch has some kind of valve to drain excessive moisture created in colder environments. The BMW bulletin number is S.I. B11 08 03