Coolant problem?

Does anyone have any idea why the coolant level in the radiator reservoir in my '97 Honda Civic keeps rising above the max line? (I’ve been checking the level when the engine’s cold.) I mean,is this a warning sign of a problem or normal operation? The coolant looks clear, looks fine, and the car is running smooth.

Changes in temperature of the engine will change the level. Going over the full mark is not a problem, unless it is somehow is going higher and higher, which is not likely unless oil is getting in there. Check you oil to make sure it is at the right level and looks normal.

It is possible that a malfunctioning radiator cap is impeding the return flow. When the engine is cold, remove the cap and examine the level in the radiator itself. If less than full, replace the cap.