Coolant in oil

[offshore 25]

I have a rebuilt 1980 470 mercruiser. I removed the side tappet cover to fix an oil leak and noticed a small amount of antifreez in the oil in this area. The oil is not milky however I have noticed steam comming out of the valve cover vent hose to the flame arrester when the engine is warm. The engine does not overheat and runs very well. Any advice on what could be causing this? <br /><br />Thanks...

 

[Haut Medoc]

Re: Coolant in oil

Welcome to iboats Are finding that you need to add coolant frequently?....JK

 

[Laddies]

Re: Coolant in oil

First don't run it with anti feeze in the oil it will destroy the bearings,if its not blowing bubbles in the coolant (which would be a head gasket) then it's probably the seals on the cam between the pump and camshaft

 

[offshore 25]

Re: Coolant in oil

How will I know if there are bubbles in the coolant? I changed the oil and it was not milky. I was thinking head Gasketleaking coolant into the oil because there is nothing leaking out of the hole in the front cover. Are there some tests I can do to narrow it down to one or the other? as far as how much coolant I loose, about a 24oz cup in about a 100 mile fishing trip. Thanks,,,

 

[Laddies]

Re: Coolant in oil

When the engine is idleing and the pressure cap is off a leaking headgasket will ussally blow bubbles in the coolant

 

[Haut Medoc]

Re: Coolant in oil

Any loss of coolant is too much. You really should find it as quickly as you can. Bubbles in heat exchanger would be one symptom, as Laddies points out. There is an easy test to tell if there are exhaust gases present in the coolant.....I don't know enough about the 470 other than it was an odd combination with the block being mabe from one material & the head something else, making them prone to head gasket leaks. A compression test & a leakdown test would be helpful here. Wait for more feedback from those who are more familiar with your engine.......P.S. Go to the 'search' function & look around in there I'm sure that you will find helpful info there.....JK