Ok, I have a 1980 6 Series with the rare euro M90 engine - It's been running ok since I've gotten it but would like to get some feedback on whats been happening recently.

From cold start, it blows out greyish/white smoke (If I rev the car, it blows a lot of smoke) for a about two minutes while it warms up and the idle is irratic... it blows a little water out the tailpipe too, which I figure is condensation.

The smoke goes away after the car is warmed up and the smoke disappears completely. After that it runs great.

The smoke doesn't smell like coolant, it just smells like exhaust, and the liquid that comes out of the tailipipe is water for sure.

I'm worried that it might be the headgasket, but there doesn't look to be coolant in the oil, or vice versa, and the car doesn't overheat. I don't smell coolant burning ever, and the coolant level seems to stay right where it should be.

Stumped :(

My guess is that your engine is running very rich on startup. The white smoke would be unburned gasoline. The rough idle that smooths out after a couple of minutes also point to the system that controls the engine idle on startup.

Since I don't know how the startup idle is controlled on your engine, I can't be much help. Sorry.

Does anyone here know how the startup idle is controlled?

You might try asking this in the 6 series forum.

i have the same exact problems including condensation in the exhaust.. i think its the head gasket too

I asked my mechanic about this bcz I have the same in my car, and he said in cold days this is absolutely normal. Even though I don't know what causes it.

Wait, you say it goes away after 2 minutes or so? If you are absolutely positive of this, then I'd say you're fine. Maybe you could have a friend drive behind you while you step heavily on the gas. Sometimes you cannot see the white smoke yourself.

Wait, you say it goes away after 2 minutes or so? If you are absolutely positive of this, then I'd say you're fine. Maybe you could have a friend drive behind you while you step heavily on the gas. Sometimes you cannot see the white smoke yourself.

Did the friends thing - the smoke goes away when I start to drive the car and it warms up to operating temperature.

Did the friends thing - the smoke goes away when I start to drive the car and it warms up to operating temperature.


I'm almost 100% sure you're fine then.. unless you're experiencing other problems, but honestly that's just condensation and can take a few minutes to disappear.

I'm almost 100% sure you're fine then.. unless you're experiencing other problems, but honestly that's just condensation and can take a few minutes to disappear.

I don't think it's condensation cause it's excessive when I rev the engine.