Volvo MD11C - Blow By

[dhostett]

My CD33 has original Volvo 11C. Engine runs like a champ after cleaning out exhaust manifold and replacing mixing elbow etc. last winter. However, after running engine for any length of time, the bilge area forward of engine, hoses and wires etc. run through bilge area get a light coating of black oil residue. I am saving my $ for an eventual engine replacement but would like to get a few more years out of current diesel, and she does run well otherwise. Suggestions on any short term actions to minimize blow by would be appreciatged. Thanks Damon

[Wayne Grenier]

there is rebreather hose that goes from the oil filler cap to the air cleaner-is yours disconnected? missing? blocked?

[S/V Necessity]

Does the residue seem to be eminating from a particular source? Is your ail filter saturated with oil? If so can you examine the air filter and see where the oil is coming from? You mention blow by, do you mean a leak in the cylinder? Do you already know if it's blowing back through the valves, or past the rings?

If you have a situation where the pressures in your crankcase seem elevated, it can very often be due to things other than worn out pistons and rings. For example it can frequently be a PCV valve in cars. Most engines have some mechanism to release and re-route these gases, and they frequently gunk up. I'm not familiar with your engine in particular. But knowing the source of the oily film would help alot.

However *if* everything is functioning properly, and the only thing wrong is your engine is in need of a rebuild... Then I'd suggest trying a thicker oil in the interim.

[Oswego John]

Hi Damon,

From what you say, it sounds like the engine is in pretty good shape. Why are you contemplating installation of a new engine?

Get the engine compression checked. If it starts up okay, the rings sound okay. The blowby might be caused by worn valve stem guide seals.

I'm not too familiar with your engine, sorry. Usually blowby fumes are carried by a hose from the crankcase breather to the combustion air intake, where they are recycled in the combustion chamber.

I have been using an additive to the oil for a long time, it's called Lucas oil Stabilizer. This product renews and restores tired engines. Some of the readers tried it and don't care for it. I have had great results with Lucas. The biggest problem I have noticed is that people don't use it in the right proportion, volumewise.

I suggest that you Google "Lucas Oil Additive". Read up on the stabilizer product and decide for yourself if it's right or not for you.

Good luck,
O J

[Oswego John]

Ckeck out the time of day that the first three responses were sent in.

O J

[Al Levesque]

Any chance that it is not oil? I have seen black coating on the front of the engine from vee belts.