white smoke!!

[Danny320i]

I recently changed the battery on my 320i and now i seem to be getting excessive white/grey smoke from the exhaust where as before there was absolutely nothing.It is due a service but the coolant levels are fine and not dropping and the oil looks good and its not overheating. The new battery is a bigger one than was previously on it. Is there any way me changing the battery could cause the smoke or is it because its due a service or could it be something else? Help would be appreciated, cheers..

[steve_k]

at this time of year the old m20 does create a fair bit of steam.

doea it go away after driving for a while?

also, might sound daft but sniff it. You'll know if it's steam or smoke.

cant see why the bigger batter would make it smoke, as i've got a battery from a 3L merc sprinter derv donkey in my 325i & no smoke.

[Brianmoooore]

Battery change is irrelevant.
White 'smoke' is condensed water vapour, and large quantities of water vapour are produced as one of the normal combustion products of petrol. Depending on weather conditions and air temperature, the water vapour produced may or may not condense when it exits the exhaust pipe, but if it does, then you see white 'smoke'.
If the coolant level is stable, then the only source of water vapour in the exhaust gasses is the combustion of fuel.
If the smoke is blue or black, then you do have problems, but still nothing directly due to the battery change.

[mcbonio]

I think your 320i has elected a new pope, either that or it's just steam from the exhaust as it's now getting colder and that water vapor is now visible... kinda like your breath on an icy morning.

[Danny320i]

Cheers fellas,just seemed a coincidence the smoke started after the battery change although i did change it because of the recent freezing weather. Thought it might be water vapor but just seemed to be more of it than other cars on the road. I'll keep an eye on it. Thanks again..

[mcbonio]

M20s always chuck out loads of steam, if your ever unsure put you hand in it, it will leave your hand moist, also give it a smell.!

[Brianmoooore]

Part of the reason is the high quality of BMW exhaust systems. The exhaust gasses struggle to heat such a large quantity of metal to a high enough temperature to keep the gasses well above 100 degrees when they exit the tail pipes.