M20 engine just started smoking - any ideas please?

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old_skool
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Post Sat Sep 02, 2006 3:56 pm

Hi,

Being new around here I need to ask a question (here we go I hear you say). :D

Up until recently I haven't had that much working knowledge of the M20 engine being a BMW 2002 entusiast with M10 engines. However I had the opportunity to buy a one owner 50,000 mile 1988 320i with absolutely no rust and near perfect overall condition. The idea being I would use it while I was working on the '02 over the winter.

Therefore I wanted to make sure the 320 was okey dokey and carried out a full service. My problems began after the oil change was carried out. Now the car produces blue smoke at idle and at revs, although it doesn't get any worse under high loads? like I would expect with valve seals etc.

The oil was correct semi synthetic 10 40 and was flushed first with 4 litres, drained and the correct amount added (4.3 litres). Obviously I ran it up, rechecked the levels. All good text book stuff.

After the oil change it began the smoking, bear in mind there was no smoke at all with it being a low mileage car prior to the service. I have considered valve guide seals or the possibility of a bad oil control ring brought on by the nice new oil but it just doesn't seem to fit.

I did the cam belt today and have noticed that the air intake hose from the airflow meter to the inlet manifold has a pool of clean oil in it. Which leads me to believe their may be a breather problem.

I took it for an MOT at main dealer yesterday and it went through fine hence the emmisons are ok. I definitely haven't overfilled the oil and am confident this is all tikkityboo.

Any suggestions please??? :?
koos
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Post Sat Sep 02, 2006 6:00 pm

Hey Buddy, Welcome!!!

When I used to work on Honda's we found that they smoked with Castrol Magnatec oil in, changed to Castrol GTX and it cured it, dont know why but its worth a try. Try another brand maybe. Running my 320 on Mobil 1, no probs with it, just pricey. HTH
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old_skool
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Post Sat Sep 02, 2006 9:18 pm

:mad: Hey thanks, I do have some other brands and think you've got a good point but I'm still a little concerened that there is an oil aspiration :wink: issue other than the normal problems. I refuse to believe the valve guides are at fault because the oil somke doesn't worsen under load..

I really need to know whether or not finding oil in the intake pipe after the AFM is noraml so I can rule it out before I rip the head off and check the bores and rebuild the head.

The trouble is with the M20 engine is that not enough techies see them any more in the main stream like they used to so even many of the specialists have moved on and forgotten what they know! Or at least that is my humble opinion.

Many thanks to everyone for the welcome and you guys run a great forum. I am a member of the BMW k1200s motorcycle forum and that attracts the same logical and quieter responses rather than the RS turbo or subaru brigade. I know I'm gonna get hung for that statement :x

I just can't help it, I love BMW cars and motorbikes! :wink:
koos
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Post Sat Sep 02, 2006 9:49 pm

Valve guides or seals? See if it smokes on start up in the morning or while running on compression going down a hill and then put your foot down, valve stem seals if it does. It is weird how its just after the oil change :?
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E30Adam
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Post Sat Sep 02, 2006 11:22 pm

If you've got oil in the AFM\TB corrugated hose then the chances are your rocker breather pipe is clocked or collapsed, a common problem.

Have a look, one end is attached to the rocker cover and it goes under the inlet manifold and attaches to the side of the TB.

They tend to get blocked and can collapse because they get hot a lot as a result of their posistion.
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2.8 Litre M20 powered - Essen Sie meinen Staub biatch
mrLEE30
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Post Sun Sep 03, 2006 5:38 am

have you overfilled it with oil?? can cause above symtoms too! failing that Nicorete patches are a good way to stop smoking winkeye

mrlee
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old_skool
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Post Sun Sep 03, 2006 9:42 am

If you've got oil in the AFM\TB corrugated hose then the chances are your rocker breather pipe is clocked or collapsed, a common problem.

Have a look, one end is attached to the rocker cover and it goes under the inlet manifold and attaches to the side of the TB.

They tend to get blocked and can collapse because they get hot a lot as a result of their posistion.
Thanks guys, I suspect that the oil isn't supposed to be inside the AFM hose hence i'll rip the breather out later and check.

MANY THANKS TO YOU ALL ! :D