my BMW 328 (straight 6 engine) has started smoking. N reg car, 131000 miles (not exactly low mileage i know)

its fine mostly, doesn't smell of burning oil when its running normally, exhaust doesn't look smokey.

I generally don't red line the engine. when getting onto motorways i do rev up to about 4500 (redline's somewhere over 6) and i very rarely go on the motorway. the other day i noticed a cloud of smoke following me as i accelerated on the motorway in 2nd gear engine sounds otherwise healthy,

what could be causing this? could it be oil pressure too high? what could be causing this?

does this engine suffer with liners like some other beemer lumps? have you tried a compression test and/or checked for any leaks in the engine bay?

A friend had an r plate 328 and that had covered far more miles and was fine, not that this helps, sorry.

Blocked breather system, worn valve guides/ stem seals or worn pistons/rings bores. Could just do with a bit of a clear out?

do a search on google, for BMW Nikasil

some 6 pot engines from 1995 -1998 had nikasil coated bores, which become damaged by sulphur in the petrol

a lot were recalled nad had new (non nikasil) blocks fitted to rectify the problem

a google search or a call to BMW uk should tell you if yours was/could be affected

this page

might help


Ray

[Edited on 31/8/07 by rayward]

Could be the old Nikasil chestnut if it's on its original engine.

Do a search for BMW Nikasil on google

cheers guys (fingers crossed for a blocked breather system!)

i'll have to put it in the garage for compression etc.

when the do gas analysis for the MOT, would burning oil affect any of the readings? just had an MOT last week you see. could help to work out if there's worn valve guides/ stem seals or worn pistons/rings bores, and is maybe a blocked breater system, that only really affected a high revs/load

I have that engine in my 528. Its manufactured during the nikasil years and has 163000 on it with no worries.

Nikasil probs usually show up as a poor idle rather than smoke. It should be silky smooth at idle with no bucking or anything untoward.

Does it start easily? Sign of low comp if its hard to start...

I would have thought if its been serviced regularly its unlikely to be anything major - those engines are built really well.

Im reckoning valve stem oil seals or as has been said blocked breather or something similar?

Geoff

never had a problem starting (well, apart from flat battery...) always idles real smooth, last night, sitting in the car chatting to my mate with the engine going, so smooth you'd not have known the enging was running. very little vibration through the gearstick etc.

every now and then there's a bit or a kick from it on idle, and you feel the car rock a tiny bit. i put that down to it maybe being time for new spark plugs or something.

as far as i can tell, engine's still the original one,

oil's real clean too. bought it from a friend last year, all the papers with it, bmw services etc, oil was new last year, and still spotless

[Edited on 31/8/07 by blakep82]

maybe it is feeling bored and wants a really good thrash with some redex in the petrol, this doesn't fix anything but will blow any crap out from todling around all the time!

Caber

last time i used redex, my fuel hoses kept burting! that was on my 318 though.

i go on the motorway, maybe once every 2 weeks for about 60 miles (to my mates house in glasgow), and i live at the top of a long, boring road on a hill, gets all the cobwebs blown out there, only on a warm engine though