So, Here is my problem hopefully some of the Guru's on here can help me out. Starting about 6-7 months ago I noticed a little white smoke coming out of the exhaust at idle, and once the car was shut off a little would wisp out even in warmer temps (70+) and more recently it is getting worse. I let the car idle for about 5-7 minutes while I was waiting in line at the ATM and when I drove away Big cloud of white smoke (though my car was literally on fire since that happened two weeks prior thanks to a melted Valve cover on the Nurburgring). No CEL and the car felt/ran fine. Got on the auto bahn and hammered it to about 130 MPH with a friend behind: No smoke. Saturday on the dyno: Idle for 2 minutes then blip the throttle and a little poof then nothing through to 5th at redline. I am at a loss. PCV delete backing up fumes?, Turbo burning a little oil? Piston on its way out? Completely normal for a modded R55/56? Any insight would be appreciated.

-Brian

 

White smoke is typically from burning coolant in the combustion chamber or incomplete combustion usually from cold starts in low ambient temperatures. Check the spark plug tips too. That will give you some clues.

Have you noticed that your coolant expansion tank is starting to run low? Normal evaporation over the long term is fine, but the engine shouldn't be drinking coolant.

Do you see bubbles in your expansion tank while the engine is running?

It wouldn't hurt to buy a combustion gas test kit to see if you're genuinely getting combustion gas in the cooling system before you go nuts tearing an engine apart.

 

White smoke is most likely coolant. A common failure in the R53 is the oil cooler gasket. That allows coolant to mix with engine oil. Another way it could burn coolant is from a failed head gasket. Check your compression in the cylinders. Also check your oil. If it's milky- that's coolant.

 

Another vote for coolant.

 

I did an oil change on my older car, left it a lil above the high mark on the dip stick, thinking I can burn it off if I floored it on the freeway.. There was A LOT of white smoke coming from my tail pipe. Came back home drained it within the max and min.. all was good.

 

Still need to check the plugs. Coolant level has not changed even a little bit. No bubbles. I have ran through the usual stuff and am wondering if it is just normal for my car.

 

Vent crankcase to atmosphere (temporarily) and see if it goes away. Otherwise, it's coolant.

DOC

 

The "white smoke" will smell sweet (or at least somewhat funky) if it is coolant.

If it doesn't smell like coolant, and it doesn't smell like fuel, it is either just plain water that got into your engine somehow, or maybe oil. Though oil smoke is generally more "blue" than "white".

Note that it is normal to have a little water in the exhaust, especially after sitting overnight and cooling off. Water is a normal byproduct of combustion, and it will condense inside the exhaust when the latter cools off. That's why you often see drips coming from the tailpipes of cars and trucks first thing in the morning. It should never be enough water to show up as "smoke" in the exhaust, though.

 

just recently i was detailing my 08 MCS and when i went to start the car to move it, it was smoking as well. for about a minute white smoke was coming out. been running stage 3 lately due to upgrading my exhaust and thats when the smoke started. now im in this thread trying to figure out this isuue. i have the PCV delete as well

 

Mamut - How long ago did you install the Riss Racing downpipe? I noticed white exhaust mostly after idling almost immediately after installing my RR catless DP. I did a secondary cat and resonator delete as well, so I'm assuming it is just because the exhaust doesn't have a cat to filter it out anymore.

 

If you know someone with an emissions machine have them wave the wand at the exhaust and then over the coolant tanks and oil cap, you will get emissions out of the coolant tank when the HG blows sometimes, you should notice antifreeze getting low and sometimes the oil will start looking like frothy yellow milk on the dipstick.