Oil in air filter

[Luis Terreforte]

Hello.
I recently purchased a 1981 380sl. While cleaning the engin conpartment I noticed that there was a considerable amount of oil on the air filter and around the filter assy. I also noticed a vapor coming from a hose connected to the valve cover. Is this normal or am I looking at an expensive repair?

[MTI]

Excess "air" pressure that builds up under the valve cover is vented to the air cleaner. If the pressures are sufficient, it will also push valvetrain oil thru the system, although there is usually an oil baffle that prevents most of it from getting to the air cleaner. An excessive amount of oil resulting from a lot of air pressure build up could be a sign that there is a compression leak, either from the valve seals or the valves themselves, allowing combustion chamber pressurization to leak out into the camshaft/valvetrain area under the valve cover.

[Larry Delor]

What weight oil are you using?

[Luis Terreforte]

Originally Posted by Larry Delor

What weight oil are you using?

I'm using 10w30 oil. Should I be using something diff.?

[Luis Terreforte]

Originally Posted by MTI

Excess "air" pressure that builds up under the valve cover is vented to the air cleaner. If the pressures are sufficient, it will also push valvetrain oil thru the system, although there is usually an oil baffle that prevents most of it from getting to the air cleaner. An excessive amount of oil resulting from a lot of air pressure build up could be a sign that there is a compression leak, either from the valve seals or the valves themselves, allowing combustion chamber pressurization to leak out into the camshaft/valvetrain area under the valve cover.

How can I verify excessive air pressure. Where is the oil baffle?

[sbourg]

Excessive pressure typically also comes from 'blowby' gasses passing the piston rings into the crankcase - which is vented thru the head into the valvetrain/cam area. This is a 'bottom end' issue then, and would require at least a complete rebuild. To rule this out - or narrow to either this or damaged valves - a compression and leakdown test.

Steve

[Luis Terreforte]

Thanks for the info. I really want to narrow down this problem before I spend too much money just trying to troubleshoot.

[Larry Delor]

At the risk of starting an oil thread, personally I would use 20W50. If you are reluctant to go with that, I would at least use a 10W40 this time of the year.
For me, that 30 is just too thin.