08/23/2026
Your vehicle’s thermostat is basically a gatekeeper for the cooling system. When it wears out, it usually gets stuck in one of two ways:
🔒 Stuck Shut: Coolant can’t flow to the radiator at all. This causes engine temps to spike rapidly into the red zone (especially in traffic) putting you at risk for severe overheating.
🔓 Stuck Open: Coolant flows constantly without stopping. The engine struggles to reach its proper operating temperature, leading to poor fuel efficiency, weak cabin heat in winter, and an unexpected Check Engine Light.
Read more about your vehicle’s thermostat in our latest blog👇
A bad thermostat can cause engine overheating or poor performance. Learn the warning signs and when to schedule a cooling system inspection in Phoenix.