1998 740il part time smoke

[boomer1]

My 740il sometimes would blow smoke ( at least once a day ) specially after a few miles driving it. I would hear a rattle, then white smoke will come out of the exhaust. I have been using sae5-30 oil, Car runs execellent and smoooth has 245k miles.

Any suggestion is greatly appreciated.

[brettski]

The Rear Manfold Cover (aka OSV) on the M62 engine is a known weakness, although it is usually a puff of smoke on startup. You can test for a failed unit by starting the engine and then letting the idle settle, then pull the dipstick and listen for the idle to drop and then recover, and a slurping noise from the dipstick tube.

There is a good write up on this site which I followed. Rear Manifold Cover aka. OSV | BMW 740iL | Magnum

Its not a hard job if you are patient, but its a tight space to work on at the rear of the engine.

[boomer1]

Got it thanks.... I'll test today and let you know the outcome.

[BadBmr]

The same thing was wrong with my 2001 740. I followed Brettski advise and now it runs as good as new.

[boomer1]

Thanks for the input. I bought the parts online and waiting for it. In the meantime, I noticed one of the rubber host attached to the manifold was bad. i changed it immediately and now I have less puff of smoke coming out and my check engine light went away.

[brettski]

Do the dipstick check again to see if that has gone as well. Also check the gaskets around the intake manifold between the AMS and the throttle body.

[Jack Dabsy]

Bloody good stuff, as always Brett

[boomer1]

Will do. thanks.

[boomer1]

after replacing the Crankcase vent ( rear intake Manifold ) I'm still getting part time smoke when starting in the morning, also when driving, it would hear a rattle sound then a puff of smoke.
The car runs great, idle is good. Any other ideas that might cause the part time smoke?

Thanks.

[brettski]

So its white smoke, it could be something to do with the transmission breather?
Can you tell where the rattle noise is coming from?
How long does the rattling noise last for?
Can you force the noise to happen?
Will it only happen after a short period from take off?

[boomer1]

It would rattle under the car for a short period, then smoke would comeout on the tail pipe. It's more constant when the car is still bit cold. when it's been running for more than 15mins, it doesn't blow smoke.

[brettski]

I have heard a rattle noise from my transmission on the first take off for the day when the transmssion is due for a service (not sure of the cause). The noise has disappeared each time I have had the oil and filter changed, but I hadn't noticed any smoke. Maybe get the transmssion serviced and have them check the breather line and related apparatus.

[boomer1]

Thanks for the suggestion. I'll try that. could it also be that I installed a bad Crankcase vent? I bought it in ebay cheap.

[boomer1]

in addition, How about the Oil Seperator Valve part#1115 1747 066? could possibly be blocked causing smoke when cold?