Thermostat Replacement
Your engine thermostat controls the temperature at which coolant begins to circulate through the radiator, keeping your engine in the efficient operating range that maximizes performance and minimizes emissions. When a thermostat fails — either stuck open or stuck closed — the consequences range from poor fuel economy and slow heater warm-up to catastrophic overheating. At Dobbs Tire & Auto Centers, our ASE-certified technicians have been diagnosing and replacing thermostats since 1976. With 150+ locations across the Midwest and South, this straightforward but important repair is easy to address.
A thermostat is a simple, affordable part that plays a critical role in engine health. If your temperature gauge is acting unusual, schedule your inspection online today.
What Does the Thermostat Do?
The thermostat is a temperature-controlled valve located in the cooling system — typically in a housing where the upper radiator hose connects to the engine. When the engine is cold, the thermostat remains closed, preventing coolant from circulating to the radiator. This allows the engine to reach its optimal operating temperature quickly. Once that temperature is reached — typically 195 to 220 degrees Fahrenheit depending on the vehicle — the thermostat opens, allowing coolant to flow to the radiator for cooling.
Thermostats fail in two ways. A thermostat stuck closed prevents coolant from reaching the radiator, causing the engine to overheat rapidly. A thermostat stuck open allows coolant to circulate continuously, preventing the engine from reaching operating temperature — resulting in poor fuel economy, white exhaust smoke in cold weather, and inadequate heater output.
Thermostat Services We Offer
Thermostat Diagnosis
Our technicians use scan tool data to monitor actual coolant temperature versus target temperature and identify whether the thermostat is failing to open, failing to close, or opening at the wrong temperature. This allows us to confirm thermostat failure before recommending replacement.
Thermostat Replacement
We replace the thermostat with an OEM-specification unit and install a new gasket or O-ring for a leak-free seal. The cooling system is refilled with fresh coolant of the correct type and bled to remove air.
Thermostat Housing Inspection & Replacement
Plastic thermostat housings are common on modern engines and can crack or warp over time. When the housing is damaged, we replace it along with the thermostat for a complete, reliable repair.
Cooling System Pressure Test
After thermostat replacement, we pressure-test the cooling system to verify that no other leaks exist — ensuring that the repair you came in for isn't masking a secondary issue.
Why Thermostat Service Matters
- A thermostat stuck closed causes the engine to overheat within minutes, risking warped heads, blown gaskets, and seized components.
- A thermostat stuck open prevents the engine from reaching operating temperature, wasting fuel and reducing heater effectiveness in winter.
- Modern engine control systems set fault codes when coolant temperature doesn't reach target, potentially triggering a check engine light.
- Running an engine constantly below operating temperature accelerates oil contamination and internal wear.
- Thermostat replacement is among the most affordable cooling system repairs, with an outsized impact on engine protection.
What to Expect at Dobbs
Thermostat diagnosis at Dobbs begins with a review of your temperature gauge behavior and a scan for cooling system fault codes. Your technician will monitor live coolant temperature data to confirm thermostat performance. If replacement is needed, it's typically completed in under two hours. We refill and bleed the cooling system, verify proper temperature operation, and pressure-test for leaks before returning your vehicle. A digital vehicle inspection is included, and financing is available.
Schedule Your Service Today
A faulty thermostat is an inexpensive fix that prevents an extremely expensive failure. Schedule your thermostat inspection at any of Dobbs' 150+ locations and protect your engine from the consequences of running too hot or too cold.
An overheating engine or temperature gauge climbing into the red, an engine that takes a very long time to warm up, poor heater output in winter, a check engine light related to coolant temperature, and poor fuel economy can all point to thermostat failure.
