bmw 540 smoking

[wedged]

maybe someone can suggest whats wrong or not....

I've had a problem with starting the 540 for some time, it starts up perfectly first time then cuts out after about 5 seconds asthough turning off the ignition. after 2-5 tries it will continue to run perfectly.



Then last weekend took the car out traveled no more that 500M looked in the rear view mirror to see clouds of thick smoke, pulled into the side of the road and by this time no smoke comming from the exhaust.

i then took the car home without any obvious smoke.

read the codes which reported 139"activatiuon map cooling"


I started the car up the following day with lots of smoke initially that stopped after about 5-10 seconds.

The smoke was very dense, i thought it was quite white and it rally hung in the air for ages not atall like steam.




I have an idea what the problem is but i didnt want to sway the suggestions..

any ideas?

[welwynnick]

Can you try (carefully) putting your hand over the end of the exhaust to see what sort of smoke it is? It may be oil, soot or water, and your hand should get covered in it after a little while.

If it's oil, you have a mechanical problem, and you should get down to a good specialist straight away and dont run it any more. This is unlikely if the smoke goes away.

If it's soot, it's running too rich, which is probably a problem with the mass air flow meter (which will cause poor running) or the water temperature sensor (which will cause poor running when cold, and seems more likely). beware - this will contaminate your expensive catalysts.

If its water, you probably have a cylinder head or inlet manifold gasket leak. In this case it will be steam rather than smoke that you see, and your coolant level will be going down.

Of course it may be something obscure like a loose electrical connection or an exhaust gas recirculation fault, but I don't know much about that.

good luck, Nick

[wedged]

oops forgot to mention that the oil is clean and the water looks fine too no obvious oil/water loss

[cptsideways]

Blocked or stuck open breather valve into the inlet tract from the cam covers usually. You might possibly have worn bores which are causing excessive crankcase pressure but I'd check the valves first, also the poor start idling issue would indicate this is the fault.

[wedged]

why would it come and go?

[wedged]

the garage was suggesting a head gasket


i was thinking/hoping water/oil seperator

any ideas how i could test?

[dxb335d]

What colour is the smoke? under what load?

[wedged]

ok more information.

When i remove the dipstick while running there is a really obvious sucking sound. and the idle speed changes.

When i was doing this test there wasnt any smoke, so i dont know if it made anny difference

[David87M3]

crankcase vent valve sometimes called oil seperator.
They fail sometimes causing high vaccuam in the crankcase and small drops of oil can get into the intake and casue smoke, or the diafram inside pails and oild gets into part of the vauuam system and is eventually sucked into the engine intake casuing smoke


there about £30, fail a lot and fairly easy to replace on the 6 pot engines, no idea how hard on a v engine


its a cheap place to start
Dave

[David87M3]

have a look here
http://home.comcast.net/~vicent/osve38.html

[wedged]

Any suggestions on the best place to get parts?
bearing in mind i dont want to drive the car and kill the cats

[David87M3]

dealer I paid about £40 for mine on my 523

[wedged]

Can anyone suggest a mail order place that i can get the parts from as i dont have a car that i want to use right now.

[David87M3]

public transport no good?

Edited by David87M3 on Thursday 17th July 15:41

[peaktorque]

Common problem on the 'V' engines is that the crankcase ventilation valve fails.

Mine went on my 535. No symptoms such as you describe, but I did have a horrific squealing noise as oil was sucked out of the crankcase and into the inlet manifold. The arsewipes at my local BMW main dealer diagnosed the problem as a noisey water pump AND headgasket! This didn't make sense to me.

Thanks to help from fellow PHers I managed to trace the fault to the CVV, a £40 part that took me about 2 hours to fit!

[wedged]

For future ref. replacing the OSV did stop the smoking.

I feel pretty pissed off at the garage tho' as they suggested new heads @£2000 or finding a second hand engine at £1200+fitting........
and all it cost me was £47 +tools