2005 E46 330cd - Smoke from under bonnet and closed oil cap

[Kieran921]

Hi all,

Ive have a look over your forum but cant seem to find anything thats similar to my issue today.
A summary of what happened:

Car up to temperature, 10 miles in came to a stop at lights to feel a lumpy idle. Noticed it revving lumpy, possible misfire. (No engine warning light).
Stopped for 10 mins. Started again, engine sounded back to normal, no lumpy idle and revving up fine.
Drove another 3 miles, smokey smell coming into cab. Pulled over, opened bonnet, smoke present. Left for 10, gave it a turn over with bonnet open and noticed smokey pressure escaping from oil cap (cap closed). Car immediatly turned off and vehicle recovered. Noticed no black or white smog from exhause.

Any ideas what may be my issue here guys? Obviously right now im thinking the worst and lets face it, this isnt going to be a cheap fix! Seems there is some over pressure within the engine to me, hopefully some sort of seal?

Thanks,

Kieran

[helix402]

Maybe blocked crankcase breather valve.

[Kieran921]

Hi Helix,

Thanks for the reply, somebody else has actually recommended this too. Going to have a look today and see if i can whip it off for a check.
Thanks again!

Kieran

[Sardonicus]

I seem to recall this crankcase breather trap being a problem part on this engine

[CarsOrBikes]

renew the breather, supposed to be changed every few oil changes anyway, and will cause turbo failure if left as the pressure in the crankcase prevents oil from the turbo draining back into the sump, causing the oil in the turbine bush to cook and block little holes, then it's a matter of time, either oval bushing or locked turbine

if you suspect the breather is a problem, get the oil flushed with a good product

only my2p

[Kieran921]

Hi, just to let you know it was an unsealed/loose injector. Turns out one had been replaced but obviously not correctly. Not nearly as bad as i was expecting if im honest. Explains the gas escape underneath the engine cover! Going to give the breather valve a clean out/replacement and inspect the other suggestions as above.
Thanks for your help chaps 👌🏻
Kieran.

[Sardonicus]

Good job, thanks for the update