Bukh DV20 - Water in Oil

[BobbyMck2]

Hi, I'm new to this site so please be gentle.

I have a Bukh DV20 and I'm having a problem with water in the oil. I've replaced the water pump and bearing on advice from Bulk after a phone call to them, and it has not cured it. It's a raw sea water cooling system. If I change the oil and filter and run the engine it seems fine. Then when I return to the boat after a couple of days there is water in the sump. And when I start the engine I of course get a nice milky white mixture. So it seems to me like the water is seeping into the oil after or as it is cooling down. To my knowledge it has never been over heated. Has any Bukh owners had a similar experience or any pointers to help me. It's driving me crazy. Thanks in advance for any help

[DeepFrz]

Do you have a sea water cooled oil cooler? Sounds, like you say, that the water is getting drawn in when the engine cools but when the oil system is pressurized the water is kept out.

[seafish]

Condensation?

[BobbyMck2]

DeepFrz, there is no oil cooler

seafish, it's way too much water for it to condensation. It does condense in the rocker cover giving a white cream deposit that looks like toothpaste

Thanks guys

[shakey doug]

G'day,
A couple of things to check, 1.water backing up exhaust or a bad manifold given the quantity of water needed to alter the oil colour hard to turn over and starting problems should be evident. 2. A cracked head or a bad head joint will vent water to sump a compression test may show a problem unless it is on the cam side of the head.3. if your engine is a early series prior to the modified water pump outlet tube it may have a crack around the liner base or a leaking liner seal ring ,thermal shock causes this due to cold water full flow directed at liner base in early bukhs dv series.

Shakey.

[BobbyMck2]

Thanks Shakey, it was the old style water pump but I've now fitted a new one. The engine starts and and runs fine. I'm having trouble trying to understand what you mean by "modified water pump outlet tube it may have a crack around the liner base or a leaking liner seal ring" The new pump is the modified type. The old one was the original type which I thought must have been passing water, so I replaced it and the bearing. I fear it may be a head problem but want to exhaust the cheaper possibilities first.

[shakey doug]

G'day,
Down behind the flywheel the delivery pipe from the pump enters the block if u undo the two cap screws you can withdraw the pipe, access to the screws is pretty tight you may have to shorten one leg of a allen key. The pipe in the early model has the end cut square this allows cold water to be directed at the base of #1cyl liner latter engines have the pipe end squashed elongating the pipe end sending the water out and around the hot liner base preventing most of the thermal shock,if you turn the water off immediately after shut down the block will remain full of water leaking thru any crack or bad seal

Shakey.

[BobbyMck2]

Thanks again Shakey, I'll check that out

[BobbyMck2]

Shakey, it looks like you were bang on the money. It seems like the liner "O"rings are shot, so I guess I'll be fitting a new engine.

Thanks again