Read the overflow tank properly
Most drivers check their coolant by glancing at the translucent plastic tank under the hood. That tank is useful, and it is also easy to misread, which is why a lot of cooling problems are either missed or imagined.
The tank is the overflow, or expansion, reservoir. Coolant expands as the engine heats up and some of it moves into the tank. As the engine cools, it is drawn back into the system. That means the level in the tank changes with temperature, and the tank usually carries two marks for that reason: one for cold, one for hot.
Check it cold. First thing in the morning, before the vehicle has been driven, is the honest reading. A level checked after a drive will sit higher and can hide a shortfall.
Compare against the cold mark. Not against how full the tank looks, and not against what it looked like last week after a long run.
Never open the pressure cap hot. On many vehicles the cap on the tank or radiator holds the system under pressure. Opened hot, it can release scalding coolant. Wait until the engine is cold.
What the readings tell you
A level that stays at the cold mark for months is a healthy system. One that slowly falls below it means coolant is going somewhere, through a leak, a hose, the pump or the engine itself, and the leak is the problem worth finding rather than the level.
A tank that is overfull when cold, or bubbling, is also worth mentioning. Both can point to trouble that a top-up would mask.
Nearby stores
Fenton and Washington also offer cooling system service.
About this store
The De Soto store is managed by Cathy Bequette.
See the national cooling system page for all 33 locations.