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Coolant loss

The engine is a w code, iron block, alum heads, two valve. I have not noticed any increase in oil volume and the oil is not off color. Ihave changed the oil twice in 2 months and each time when the drain plug is loosened I get maybe 10 to 20 drops of green coolant. When this stops I continue to remove the drain plug and the dirty oil begins to flow as normal. There is however a light brown milky film under the oil filler cap. Any and all comments are much appriciated. Thanks again. Sam

Need more info about the engine. Year,make, model, miles.

If I were to guess, there is a intake manifold leak.

If it’s a GM motor, it sounds like an intake gasket leak. An independent mechanic or dealership should be able to confirm the diagnosis. Coolant in the oil is a very bad thing, the coolant displaces the oil on the bearing surfaces. Coolant is a lousy lubricant.

Ed B.

You can’t possibly get 10 or 20 drops of green coolant when you open the oil drain.

mercury 4.6 v8 2002 mountaineer 103000 miles

There are simple tests such as a pressure leakdown test to verify the cause. That test simply pressurizes each cylinder and checks to see if it holds the pressure. Failure to do so indicates a leak through the headgasket.

I’d recommend having this checked as soon as possible. This condition will cause further damage if unchecked.