Why is my car overheating but coolant is full?
Full coolant + overheating means the coolant isn't circulating properly — the most common causes are a stuck-closed thermostat, a failed water pump (impeller broken off the shaft), an air pocket trapped in the system after a recent service, or a clogged radiator. Less commonly, a head gasket leak can cause overheating without losing visible coolant — combustion gases pressurize the system and push coolant past the thermostat.
Get a free AI-ranked diagnosis for your exact year, make and model — with fair repair cost ranges and DIY-vs-shop guidance.