Page 1 of 4
Oil fumes from the head cover
Posted: Thu Aug 11, 2016 5:25 pm
by petroscf
Is this a common issue? Is it because the engine is still new?(thus meaning it is going to decrease with time/km)? Or might it be a technical problem?
Re: Oil fumes from the head cover
Posted: Fri Aug 12, 2016 12:14 pm
by Dammizi
fully rebuilt my engine including honing of block, new pistons & rings, fully rebuilt head, including valve guides and stem seals.
after the rebuild I still get a bit of fumes from my engine running it on 10W40 oil, but after swapping over to 20W50 oil fumes almost completely disappeared but still slightly evident
Btw I just finished doing my first 1000Miles on the engine and results are consistent throught usage..
Re: Oil fumes from the head cover
Posted: Mon Aug 15, 2016 8:46 pm
by Jeroen
Must be me, but where exactly are these fumes coming from then? Leaks are never meant to be...
Re: Oil fumes from the head cover
Posted: Tue Aug 16, 2016 5:48 pm
by Dammizi
Jeroen wrote:Must be me, but where exactly are these fumes coming from then? Leaks are never meant to be...
Assumed he meant from the rocker cover breather?
Re: Oil fumes from the head cover
Posted: Tue Aug 16, 2016 7:04 pm
by Jeroen
And since when is that a check or indicator? Bit lost here haha
Re: Oil fumes from the head cover
Posted: Tue Aug 16, 2016 10:13 pm
by Dammizi
Jeroen wrote:And since when is that a check or indicator? Bit lost here haha
well I'm guessing just cause normally engines shouldn't smoke through the rocker cover breather.

but then even mine does smoke through the breather after rebuilding the engine...
Re: Oil fumes from the head cover
Posted: Sun Aug 21, 2016 6:33 pm
by petroscf
The head cover is called a rocker cover? If yes, then yes right there's a brether there on M10 (like a small exhaust pipe?)
Newly built as I already said, my engine gives from this breather rather lots of fumes, which, when they come out become liquid again and spill a bit around. Some smell comes inside the cabin(but that's probably a matter of a rubber missing in my car)
Will take a picture to show exactly what I mean
Re: Oil fumes from the head cover
Posted: Sun Aug 21, 2016 6:37 pm
by petroscf
Mark gave me a nice idea while discussing the matter: he proposed that we connect the breather to a long tube and send the other tube end to the rear of the car somewhere. At least until these fumes decrease significantly
Will discuss this with my mechanic to see how easily doable it is
Re: Oil fumes from the head cover
Posted: Sun Aug 21, 2016 11:04 pm
by Dammizi
what I sometimes do is attach a tube long enough to reach the lower part of the engine bay, that way the fumes blow outof the way and not into the cabin. Btw, yes the top of the head we usually refer to it as the rocker cover and the small exhaust pipe like thing is the breather, this from factory is connected to the intake by a breather hose, but dont use it as it will leave the intake full of oily gunk...
Re: Oil fumes from the head cover
Posted: Sun Aug 21, 2016 11:11 pm
by BertjeConti
Normaly the breather hose on the valve cover (rocker cover) is connected to the air filter box (carburettor) or to the throttle body (injection) , and these fumes are burned again by the engine.
Re: Oil fumes from the head cover
Posted: Mon Aug 22, 2016 2:31 pm
by petroscf
We already connected it to an oil collector can, but still fumes escape
If it is not good to have oil back into the engine, then why did bmw connect it to the inlet again?
Re: Oil fumes from the head cover
Posted: Mon Aug 22, 2016 2:46 pm
by petroscf
Re: Oil fumes from the head cover
Posted: Mon Aug 22, 2016 3:13 pm
by Dammizi
petroscf wrote:We already connected it to an oil collector can, but still fumes escape
If it is not good to have oil back into the engine, then why did bmw connect it to the inlet again?
well I always thought that this was done due to emmisions regulations and controls in many countries, to reduce fumes escaping outside and especially into the cabin for drivers safety. in many countries it is mandatory that the breather hose is left connected to the intake manifold for emissions control. but here in Malta this is not controlled so many of us disconnect this to prevent filling the intake manifold with the oily fumes...
Re: Oil fumes from the head cover
Posted: Mon Aug 22, 2016 4:29 pm
by BertjeConti
Yep
Emmission regulations
Re: Oil fumes from the head cover
Posted: Sat Aug 27, 2016 1:50 pm
by petroscf
Let's see if it is just about some oil fumes from the breather, finally... :
Did about 150 km yesterday, to be the car's first short trip out of Athens area
Opened the hood, and there was oil spilled almost everywhere...My nice and clean engine bay - and engine- is now so dirty! Also, checked the oil level, and quite a big quantity was gone, for such a short (even though quick!!) drive. Had to top up today before setting off to return.
On the other hand, a Merc slk 32 amg (or so I could read on its rear) couldn't loose me from its mirrors before 180kph
