Thermostat
The thermostat controls how quickly your engine warms up and keeps it at the right operating temperature. If your engine overheats, takes forever to warm up, or the heater blows cold, a stuck thermostat is a common and affordable cause that's worth checking first.
Find a TechnicianCommon causes
- Thermostat stuck closed, blocking coolant flow and causing overheating
- Thermostat stuck open, leaving the engine running too cool
- Corrosion or mineral buildup from old coolant jamming the valve
- A worn-out spring or wax element that no longer opens at the right temperature
- A failed thermostat gasket or seal causing a coolant leak at the housing
Frequently asked questions
Can a bad thermostat damage my engine?
Yes. If it sticks closed, coolant can't circulate and the engine quickly overheats, which can warp the head or blow the head gasket. It's a cheap part, so replacing it early prevents far more expensive repairs.
Why does my heater blow cold air?
A thermostat stuck open keeps the engine from reaching full temperature, so the cabin heater never gets hot enough. Replacing the thermostat usually restores proper warmth and engine temperature.
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