why is my car overheating but it has coolant in it

Coolant’s present, sure, but overheating usually means the heat isn’t leaving or the coolant isn’t moving.

Don’t keep driving; heat is the silent assassin of head gaskets and wallets.

Likely culprits include:

• Stuck thermostat or jammed radiator cap preventing proper flow/pressure.
• Airlock after a recent top‑up or service; system needs a proper bleed.
• Radiator fan not kicking in (blown fuse, bad relay, dead motor, faulty temp sensor).
• Blocked radiator or collapsed hose choking circulation.
• Failing water pump or slipping belt/eroded impeller.
• Combustion gases from a blown head gasket pressurising the system (bubbles, milky oil, sweet white exhaust).

Get a pressure test, check for fan operation, and bleed the system before you turn the engine into fondue—cheap checks now beat an expensive rebuild later.