Repair cost · Cooling, AC & Belts
Thermostat Replacement Cost
Average cost: A thermostat replacement costs between $616 and $716 on average, according to RepairPal's national estimate. Labor accounts for $195 to $286 and parts for $421 – $429. The figures exclude taxes and fees, and your price depends on your vehicle and where you live.
| National average, parts and labor | $616–$716 |
|---|---|
| Sources checked | 1 |
RepairPal puts the national average for a thermostat replacement at $616 to $716, before taxes and fees. Based on the midpoints of RepairPal's ranges, labor makes up about 36% of the bill and parts about 64%. Your quote can be higher or lower depending on the make, model and engine of your car, the parts used and local labor rates.
Cost breakdown
| RepairPal national average | |
|---|---|
| Total | $616 – $716 |
| Labor | $195 – $286 |
| Parts | $421 – $429 |
Source: RepairPal estimate, last updated September 3, 2026. Excludes taxes and fees and does not adjust for location.
What the thermostat does
The thermostat is a valve between the engine and the radiator. When the engine is cold, it stays closed so the engine warms up quickly. Once the engine reaches operating temperature, it opens and lets coolant flow to the radiator. Many modern thermostats are part of a housing assembly, and some are electronically controlled.
Signs of a bad thermostat
- Stuck closed: the engine overheats, sometimes quickly, even with plenty of coolant.
- Stuck open: the engine takes a long time to warm up, the heater blows lukewarm air and fuel economy drops.
- The temperature gauge swings up and down.
- A check engine light with a code for engine temperature below the regulating temperature.
- Coolant leaking from the thermostat housing.
Why the cost is higher than many people expect
On older engines, the thermostat was a cheap part in an easy-to-reach housing. On many current engines, the thermostat is built into a plastic housing assembly, sometimes with sensors and an electronic control, and it may sit low on the engine or behind other parts. That is why parts make up most of RepairPal's average for this repair.
Fix it promptly
A thermostat stuck closed can overheat the engine and damage the head gasket. A thermostat stuck open is less urgent but wastes fuel and can affect emissions and engine wear. Either way, it is cheaper to fix now than later.
Related parts
Because the cooling system is drained, it is a good time to check hoses, the water pump and the coolant condition. If the coolant is old or contaminated, a flush may be recommended.
Can you do it yourself?
On engines with an accessible housing, a thermostat swap is a common DIY job. The key steps are using the correct coolant and bleeding air from the system afterward; trapped air can cause overheating. If the thermostat is integrated with sensors or hard to reach, a shop is the safer choice.
Questions to ask the shop
- Is the thermostat a separate part or part of a housing assembly on my engine?
- Does the quote include coolant and bleeding the system?
- Are the hoses and water pump in good condition?
How the job is done
- The engine is allowed to cool, and some or all of the coolant is drained.
- Hoses and any parts blocking the thermostat housing are removed.
- The housing bolts are removed, and the old thermostat or housing assembly comes out.
- The new thermostat goes in with a new gasket or seal, installed in the correct direction.
- The system is refilled and bled of air.
- The engine is warmed up to confirm the thermostat opens and the temperature stays steady.
Frequently asked questions
Can I just remove the thermostat? No. Running without one makes the engine run too cold, which harms fuel economy, emissions, heater performance and engine wear, and can trigger warning lights.
Why is my heater blowing cold air? A thermostat stuck open is a common cause. Low coolant or a heater core problem can also be responsible.
Should I replace the thermostat with the water pump? Many shops recommend it when both are old because the cooling system is already drained.
Can a bad thermostat cause a check engine light? Yes. Many cars set a code when the engine doesn't reach normal operating temperature within a set time.
Is your quote fair?
Compare your written quote with the national range above. A quote well above $716 is not automatically wrong, because some vehicles need more parts or more hours, but it is worth asking the shop to explain the difference. Ask for the quote to be split into parts and labor, and for the parts to be listed by name and brand. If the labor portion is far above $286, ask how many hours the shop is charging and what makes your car take longer. Getting a second written quote for the same parts is the simplest way to check a price.
What happens if you wait
A thermostat stuck closed stops coolant from reaching the radiator, so the engine overheats quickly, especially in traffic or hot weather. Overheating can warp the cylinder head and blow the head gasket. If the temperature gauge climbs fast after a cold start, stop and have the car checked rather than driving on.
A thermostat stuck open is less urgent but still worth fixing. The engine warms up slowly or never reaches normal temperature, which hurts fuel economy, increases emissions and engine wear, and leaves the heater blowing lukewarm air in winter.
Choosing the part
Use a thermostat with the temperature rating specified for your engine. A cooler-rated thermostat may seem like a way to protect the engine, but the engine computer is calibrated for a specific operating temperature, and running cooler can set codes and reduce efficiency. On many newer cars, the thermostat comes as part of a housing assembly with sensors, which costs more but is the correct replacement.
After the repair
Watch the temperature gauge as the engine warms up over the next few drives; it should rise to the middle and stay there. Check the coolant level when the engine is cold and top off if needed as trapped air works out of the system.
Coolant flush with the thermostat
If the coolant is old, ask about refreshing it at the same visit, since the system is already partly drained.
Warranty
Ask whether the thermostat housing and gasket carry the same warranty as the part.