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Matt
Matt, Mechanical Engineer
Category: BMW
Satisfied Customers: 22893
Experience:  BEng hons Mech engineering, in auto industry 22 years
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i have been advised by our mechanic that it would be expensive/futile

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i have been advised by our mechanic that it would be expensive/futile to repair my bmw 3 18ci convertible (o3)
it is smoking after approx 10 mins running, the explination is that it could be a crankshaft filter? or camshaft filter etc..however he says that he cannot rule out that the piston rings need replacing as the top end compression reading suggests ? he is saying the smoke is emanating because it cant find its way out etc and is causing the pressure and the oil to over spill hence the smoke? can you shed some light please?
Steve
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Customer: replied 3 years ago.

POSSIBLE CAUSES FOR SMOKING ENGINE?

Customer: replied 3 years ago.

given the low pressure reading, couple with smoking engine- could it be piston related? or what other possibilities ? i can advise looking at engine, the left mid low section is where the smoke is coming from

Customer: replied 3 years ago.
Relist: Other.
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Hello

Ok if its got low comrpession and is using oil then yes blown piston rings are a possibility

however I'd 1st check is the crankcase pressure relief valve (PCV) these are sprung loaded and are only meant to 'burp' excess pressure every now and then. The exiting gas is piped back to the inlet , however should the valve stick open then the engine tends to suck the air out of the crankcase all the time and this carrys oil over with it.

If you remove the air intake pipe and look inside where the crankcase breather is plumbed in you may find evidence of oil.

If you do find oil replace the valve
Matt, Mechanical Engineer
Category: BMW
Satisfied Customers: 22893
Experience: BEng hons Mech engineering, in auto industry 22 years
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