1998 Oldsmobile Eighty-Eight - Getting oil out of the coolant system

My wife’s Oldsmobile is a great car. Looking throughout the engine, I can tell it’s seen it’s days but this thing last forever before having any issues compared to much newer cars I’ve owned and hear about. But, I discovered oil in my wife’s 1998 Oldsmobile Eighty Eight coolant system. It is literally all over the place.

As a picture, imagine a additional layer being added to the inside walls of the hoses, I mean everything. Then, imagine that wall being a layer of oil. I can barely recognize the bottom end of the cap at this point. Most of the coil on this cap is completely smudged with this grimy stuff.

But apparently, my wife has had this car for nearly two years now and never checked the coolant or had anything done to this car before we got married but it runs perfectly fine. You’d never guess that something was wrong with it. But I tasted the debris and did everything I could to analyze the stuff. It is definitely oil inside her coolant system.

I suspect the cause to be that of the cracked valve gasket that I believe was with the car when she got it. I can replace that no problem so long as there isn’t another issue further in the block. But as far as the oil having infiltrated the coolant system, does anyone know how to flush oil out of there or would I be looking at replacing the entire cooling system should we be keeping this car?

Thank you.

Are you sure it is oil and not the black oily sludge from Dec Cool being left in too long? The most common reason for an oil like substance to get into the cooling system is transmission fluid from the transmission cooler inside your radiator springing a leak, but you would dee bubbles of coolant on your transmission dipstick.

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I don’t rule out anything! Someone could actually have added a quart of oil to the radiator, it’s happened before.

Agree that DEX Cool makes a mess and a thorough flush and replacement with a universal cooler would be in order.

Most likely failed lower intake manifold gaskets . . . allowing engine oil and coolant to mix

This is a routine repair for a lot of shops

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I didn’t think of that route, I have never had a coolant leak from an intake manifold gasket. I don’t know if I ever owned a car that had coolant through the manifold.