I made a mistake. I thought I was adding anti-freeze, I mistakenly put about a spoon of oil into the overflow. Have I done any damage? I have not started the car since.

The oil will float. You can try to soak up as much as you can with a paper towel. Or better yet, take the overflow tank off, clean it out and put it back on.

Don’t go into panic mode. That small amount of oil isn’t going to hurt anything. Now if you want, you could stick a rolled up paper towels into the reservior to absorb the oil. If the engine hasn’t been started, the oil will be floating on top of the coolant.


First of all Thank you. I do not know how to take the overflow tank off.

Thank you. I will try that. Also, there was not any anti-freeze in the over-flow.

This indicates that you have a problem with your cooling system and should get that checked out. Just putting anti-freeze (premixed with water) into the overflow reservoir isn’t likely to do anything if your system is very low on coolant and/or has a leak.

Ok. and Thank you. There is coolant in the radiator, I just always add it to the over-flow; Is that wrong?

No, that’s not wrong, but the overflow (if everything is working correctly) should stay about half full. Empty indicates a problem.

Thank you. I will have it checked out. Have a great day.

If there was no coolant in the reservior when the oil was added, remove the hose from the radiator below the radiator cap, and point it into a container. Now pour hot water into the reservior until all the oil is flushed out.


Thank you. I will attempt that. Thanks again and have a great day.