More exhaust smoke than usual and mpg down...

[e34.535i.sport]

Ok the 535's been using more juice lately than it was and there seems to be a lot more white 'smoke' (for want of a better word) coming from the tailpipe than normal... Its not thicker than normal and smells normal (i think?). The smoke and fuel usage may be totally unrelated I don't know. The smoke seems to have increased since the cold weather set in (its really cold here now) so is it just that I can see it more due to the weather (like breathing out when its really cold)? I hope this isn't a stupid question but the amount of fumes coming out of the tailpipe seems to have changed a lot (although its been MOT'd recently with VERY good emissions). I had a search and someone mentioned in a thread that white smoke could suggest the car is running lean? If this is the case how do you go about correcting it?

The car's not loosing coolant (replaced it a month or two back with all hoses), and there's no coolant in the oil... I've checked for fuel leaks and none present (fuel filter changed 3k ago) and no other reasons to suspect a problem generally.

I'm hoping its nothing but it's enough to have caught my attention so i thought it best to check... Any ideas?

[Ferret]

*cough*newb*cough*



The exhausts on these cars are so monstrous that you should expect them to issue clouds of white steam for upto an hour after startup in cold weather...

Also I would expect these engines to use a larger amount of fuel when the air is cold and yer freezin yer **** off! The air density has changed with the temp and the engines gotta throw more fuel in to compensate.

...or someone correct me.

[repenttokyo]

do you live in a cold winter climate? your fuel mileage is going to drop noticeably.

[e34.535i.sport]

He he he thanks Ferret *cough* Rodent *cough*!

You've put my mind at rest at least to know others are finding the same thing... Cold weather was the first thing i thought of but when your sitting at lights and clouds of smoke are passing the passenger side window its a bit worrying!

What mpg are you averaging recently (if you don't mind me asking)?

Thanks again,

[Paul in NZ]

yes its normal.as Ferret says our exhausts have so much mass that they take a long time to warm up enough to actually drive all the moisture out(normal combustion by product),so the next day you get the normal steam from the exhaust and some steam coming from the accumulated moisture in the exhaust.The mpg thing may be related to the fact that as its cold the car is running rich(start up mode) for longer.Do you sit and idle before you move off?If so dont,just drive off as soon as its runing well.just keep the revs and throttle opening down for a bit.

[e34.535i.sport]

Hey Tokyo unfortunately yes! I bought the car in the spring when it was fairly warm so this is our first winter together! I've never noticed a drop in mpg before but my previous cars have been much newer and 1.9L and under!

Thanks Paul that makes a lot of sense. I have been tending to let it idle for a bit while the windscreen clears with the heater on.

Apologies for the ridiculous question, but you have made me feel a lot better about the whole thing because I was a little concerned (panicing over nothing as per usual).

[E34-520iSE]

When it's really cold here in the UK mine blows like a steam engine on startup, but there's nothing to worry about - once the exhaust dries out everything is clear again.

HTH,

Shaun M