White smoke from exaust

G

gingershoes

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My 520i auto has started smoking from the exaust. The smoke is white tinged with brown. It really stinks, not of fuel or anti freeze. It starts after about 20 minutes driving, and billows out great clouds, after a few minutes the engine starts to misfire. After stopping and running engine in park, smoke clears. Engine maintaining normal temperature.

Cooling system pressure checked overnight by by garage, no loss of pressure, also, no coolant being lost and nothing showing in engine oil.

I did read somewhere that it may be transmission fluid getting into engine but garage assures me that this is not possible.

Has anyone any idea as the car is still with the garage and they are scratching their heads.
 
Kirby

Kirby

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520i - I'm thinking this is a diesel engine? If so, we don't have BMW diesel cars in the US, so most of us will not be of much help.

I have a bit of experience with industrial diesel engines. They usually smoke white when the fuel is not being burned efficiently. Is it possible that one cylinder is not burning the fuel? This could be caused by a bad glow plug, too much fuel/bad injector, or loss of compression.

The fact that it clears up after idling is a clue that it is probably fuel related.
 
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gingershoes

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Kirby said:
520i - I'm thinking this is a diesel engine? If so, we don't have BMW diesel cars in the US, so most of us will not be of much help.

I have a bit of experience with industrial diesel engines. They usually smoke white when the fuel is not being burned efficiently. Is it possible that one cylinder is not burning the fuel? This could be caused by a bad glow plug, too much fuel/bad injector, or loss of compression.

The fact that it clears up after idling is a clue that it is probably fuel related.
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Sorry to omit, but it is a petrol engine, UK models normally have a model number such as 520d to differentiate, thanks for any help
 
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swelephant

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gingershoes said:
My 520i auto has started smoking from the exaust. The smoke is white tinged with brown. It really stinks, not of fuel or anti freeze. It starts after about 20 minutes driving, and billows out great clouds, after a few minutes the engine starts to misfire. After stopping and running engine in park, smoke clears. Engine maintaining normal temperature.

Cooling system pressure checked overnight by by garage, no loss of pressure, also, no coolant being lost and nothing showing in engine oil.

I did read somewhere that it may be transmission fluid getting into engine but garage assures me that this is not possible.

Has anyone any idea as the car is still with the garage and they are scratching their heads.
Click to expand...
Hi mate, white smoke normally idicates water getting into the chamber some way. It's strange how it clears on tick over. Oil or fuel would normally be black or blue smoke. When it miss fires, remove the plugs and see which one is wet, that will give you a clue to which cylinder it is. It may only be a tina seep of water and not enough to show. I would suspect head gasket, do a compression test on each cylinder. Cheers Mick.
 
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gingershoes

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Just to add to the knowledge base, the fault turned out to be a faulty breather valve in the inlet manifold assembly, this was causing a vacuum in the cylinders sucking in oil and burning in the cylinders. Valve assembly replaced and now perfect. Thanks to those that tried to help, cheers.
 
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