Oil in Coolant

[jstonge]

My Mercruiser 170 HP with a closed cooling system has what appears to be oil in the coolant. The motor oil is fresh and clear no sign of water. The power steering is also clear. The anti-freeze cooling instead of the typical green that it always been is now dark and oily. The engine runs perfect, no loss of gain in coolant volume, no overheating.

Any thoughts as to the source?

[Gary McKay]

My first inclination is to think intake manifold. This is an area where the coolant and oil can get together if the gasket or manifold have a flaw. It is not uncommon in the auto world and asking your local GM mechanic might help narrow the source. Consider a compression check and verifying that the cylinders all come in with pressures that are within 10 pounds of each other. If there is one out it may also be the cause and worth attention before that unwanted tow.
Gary

[planetboats.com]

Definately have a gasket leaking somewhere...

Get it fixed before you run it...

Good Luck,

Captain Dave