White Smoke + Exhaust
 

I have an 2001 A6 2.7T with 156K miles. This week after a routine check up at my Audi mechanic, I started the car [the next day] and had white smoke come out of the exhaust [after about 10m of running]. It was more evident when I let off the gas.

The engine has no noticeable performance changes [runs smooth as ever]. I just have this white smoke.

Not sure what to make of it. Any ideas would be helpful! Thanks!

White smoke is really water vapor, which should disappear after warmup. If not, then that's a sign of a coolant leak into a combustion chamber. Since your engine is smooth running with no changes, I wouldn't worry about it.

I respectfully disagree with A6Gary. If it's a coolant leak, it could mean a blown head gasket, and if so, it could kill your engine in very short order (b/c of bent piston rods). I would get the car back to the mechanic immediately and insist that he check it over. If the mechanic says nothing's wrong and the engine gets ruined, at least you'll have a leg to stand on.

Have you noticed any coolant loss?

If you do continue to drive it Id check the coolant bottle after every trip and keep a very sharp eye on the temp gauge!

Id also try and keep the car off boost as much as poss!

Pop it to a garage and they can perform different tests to check the headgasket etc!

I haven't had any coolant loss. The mechanic topped off while I was in on Friday. If it were the head gasket, i've been told I'd see performance issues including it idling or running rough of which I have neither.

I'm still going to run it back into the mechanic in the morning and see what they can find out.

Any report?

piston rods? blown head gasket will kill your motor because of poor lubrication resulting from the oil turning to ****.

Need more info...plus my experience and thoughts on it
 

I have read a bunch of these lately looking for info on my C5 smoking, but often find the info is still vague and the answers varied.

From experience, the stereotype answers are that water vapor is white and oil blue. Been there seen it, blown head gaskets and all--C1's used to eat them at the drop of a hat. But, from experience w/ my C5, the oil smoke it has clearly been exuding (and burning) really isn't blue. It's gray and arguably somewhat white when you see it. Combined with the usual start up from cold condensation it's even trickier to accurately diagnose. The smell though is a definite give away; strong exhaust/hydrocarbon type smell with oil, which you don't find w/ straight water vapor.

Suggestions: put your hand below the exhaust. Let a bit collect on your hand. Then, is it slimy slippery like oil, or just seem like water? Does it have a taste? When it splatters out exhaust if you goose the gas, does it dry on the ground like water, or stay there like oil? Does it smell strongly? Over time ( a week or two, and 500-1000 miles), is it using oil w/ out an obvious leak on the ground (or coolant likewise)?

Net, despite the color that might say water, reading this I might guess oil--no signs of water level dropping being an obvious clue. Plus it's a 2.7 which makes me think turbo's, plus high mileage. From having just worked through this on my 4.2, for what it's worth I found a specific cylinder with stem seal issues, but ultimately found what I suspect was a problem with the PCV valve. An almost undocumented part of the car, at least on 4.2's, and most all the oil smoke posts are on the suck valve, which has a somewhat overlapping function.

I dont follow. His point ( i presume) is that if there was excess coolant entering the system, it would NOT run smoothly. hense it is simply condensation "burning" off. I tend to agree.

Now a blown head gasket (or any other point of water-oil mixing) can be very serious. But again i dont get the piston rod bit. Are you suggesting we fly without warning from a smooth running motor to hydrolock? Seems pretty far fetched. Maybe i'm missing a subtlety here. Could you elaborate?

in any event - look for water in the oil and oil int eh water. actually, more likely the latter since combustion chamber pressure 9onteh bang part of SSBB) is >>> water pressure.

G

seriously how many of you have actually seen or driven a car (or this car for that matter) with a blown head gasket, or turbos.............
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thats what i thought SFTU

your car is fine, it was either of those, you WOULD KNOW