Is this a matter of M20 oil blowby or perhaps something else?

[genphreak]

Hi everyone,

Can someone please enlighten me as to the typical symptoms of a worn out M20 are?

My nieghbours e30 has a bit of oil buildup on intake side of the engine. It appears that the pipe (#11) which leads from the lower block to the intake manifold has oil leaking down it. Also, I noticed oil near the throttle housing in the intake, some was even making its way into the AFM when we pulled that recently.

Does this usually mean excesive blow by? When we bought the car inspecting the head via the oil cap none of this was noticable.

The plugs look like they are burning fine.

We are planning to do a compression test and valve adjustment. Is there anything else we should check?

http://bmwfans.info/original/images/55_p.png

Many thanks in advance, :) Nick

[E34-520iSE]

Yeah, check for air/vacuum leaks. A poor seal somewhere will result in oil going into the intake. Been there, done that, worn the t-shirt etc.

Cheers,

Shaun M

[genphreak]

That's what I was hoping to hear Shaun. We already suspect vacuum leaks and have got every a replacement pipe for every one.

Ahhh now there's be fun to be done wrenchin', time to get going

Thanks! :) Nick

[Barney Paull-Edwards]

That's what I was hoping to hear Shaun. We already suspect vacuum leaks and have got every a replacement pipe for every one.

Ahhh now there's be fun to be done wrenchin', time to get going

Thanks! :) Nick
clamp off servo pipe as well to check diaphragm leaks in servo,

[Barney Paull-Edwards]

That's what I was hoping to hear Shaun. We already suspect vacuum leaks and have got every a replacement pipe for every one.

Ahhh now there's be fun to be done wrenchin', time to get going

Thanks! :) Nick
clamp off servo pipe as well to check diaphragm leaks in servo,

[Barney Paull-Edwards]

That's what I was hoping to hear Shaun. We already suspect vacuum leaks and have got every a replacement pipe for every one.

Ahhh now there's be fun to be done wrenchin', time to get going

Thanks! :) Nick
clamp off servo pipe as well to check diaphragm leaks in servo,

[Barney Paull-Edwards]

sorry about replies, brain fade! Air vacuum leaks favourite but I had same symptoms on my M5 and it proved to be Diaphragm leak sucking brake fluid into manifold,

[Ferret]

I had these exact symptoms on an M50 from busted piston/rings...

Revving the nuts out of the engine forces enough pressure into the crank case to blow oil and crap straight out the breather lines into the intake manifold etc.

The crankcase pressure wasnt really noticable until we took the bonnet/hood off and drove off down the road under WOT with the oil cap off... even with the plastic splash cover underneath it was blowing like crazy!