Oil Getting Into Coolant

My wife has a 2000 Buick Century with about 150,000 miles on it. It has been relatively trouble free. Recently, the “low coolant” light began to come on.
She took the car into a garage where she was told there was oil in the coolant and the sensor had been compromised. The cooling system was flushed and cleaned and a new sensor installed. The “low coolant” light continued to come on. She took the car back in. She was told the wrong sensor had been installed. When she went back for the car the second time, she was told the oil in the coolant was preventing the new sensor from working and there was nothing more the garage could do. I went in and asked questions, primarily how serious was the condition, and couldn’t get a straight answer.

We are due to drive to Florida in November. My wife would like to take it to a garage there. Is it save to drive it as is? What are the implications of oil mixing with coolant? What is causing it to happen? Is it time to buy a new car and, if so, is it safe to wait until we’re in Florida?


Your biggest issue isn’t the low coolant sensor, it is the oil in the coolant. That is a major issue because it means there is a breech somewhere in the engine. Most likely, you will need a new intake manifold, that is where this engine has a history of problems causing oil to get into the coolant and visa versa. If your oil is getting a milky brown color to it, a little foamy like a chocolate milk shake, it can start causing damage to the internal parts of the engine.

Start with another shop, your shop should have known this. Get several estimates because this is not cheap to fix, usually $1500 to $1800.

I totally agree with Keith.

And don’t drive the vehicle.


GM had major problems with intake manifold gaskets for ALL their V6 and some V8 engines.

They were forced into a recall to fix this. Check with the dealer…they might do it for free. But I doubt it.

That recall had mileage and time limits

OP’s car is probably too old and has too many miles