Sudden oil loss-Yanmar

[sailorchic34]

Originally Posted by Cheechako

If a head gasket it either is going in the coolant (easily checked) or smoking out the exhaust right? (easily checked)

True, But your not going to loose a quart of oil an hour to the coolant. Either its in the bilge, out the water side of the oil cooler (assuming raw water cooled), or entering a cylinder via a blown head gasket, or from trashed/ broken rings and being burned. Or if a turbo, could be a blown seal in the turbo.

From personal experience with my broken rings, basically no rings, I was burning a quart every 12 hours. A far cry from 2 quarts in an hour. So I don't see that as high probability.

A cracked external oil line could easily leak 2 quarts in 1-1/2 hours. But the bilge would be black. Same with a cracked oil cooler except its going overboard, not all that uncommon with yanmar either. The oil sheen points to the oil going out the exhaust.

We need to hear back from the OP as to engine type.