Volvo Penta

I have a motor Volvo Penta AQD 41A in my boat, and now I have a problem that I don't get to identify. - The motor usually works, meantime after some hours of use, it expels the whole lubricating oil through the breath filter. I made the test of compression emission opening the cover where the oil is put, and I didn't notice any compression emission. I would like somebody to guide myself to I respect, because several mechanics that I consulted myself didn't give a satisfactory answer. The apparent causes would be rest in the pistons, but that is not true because the motor is not with the level of the low oil.

Thanks Fernando

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Dear Fernando:

There are seals between the oil-and-crankcase-area and internal-piston-space, at the following locations:

- pistons seals

- exhaust valve seal

- intake valve seal

- head gasket

- oil passages in engine block (and heads)

So piston seals apparently are not leaking.

I don't know how the intake manifold is run on this engine. It sounds to me like either you have:

- a faulty intake valve stem seal

- a blown head gasket

- a cracked block

- a cracked head

If it were a valve stem seal, I would have expected the exhaust valve seal to have failed. In inlet valve case, I would expect the spark plug to foul more frequently. In the both valve leaks, I would expect oil smoke to come out. Is there any smoke?

The other posters might be of more help. You are aware that there are oil-filled air filters, right? Does you engine use one of these?

David A. Smith

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N:dlzc D:aol T:com (dlzc)

"Fernando" wrote in news:

Interesting problem. There appears to be pressure building up in the crankcase over time. This could be a small head gasket leak into an oil passage, a cracked block, or any of several other paths. The difficult part is how the pressure is forcing oil out through the breather rather than just escaping. I don't have any idea of the arrangement of oil level, oil baffels, or breather tube in that oil pan. Boat motion may have something to do with it. I would suggest you take the question to rec.boat for pointers to a solution. Somebody there should be familiar with this particular engine.

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Charly Coughran

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