How Much Does a Car Thermostat Replacement Cost?

Here’s a breakdown of the expenses associated with replacing your existing thermostat: 

A. Range

The average cost of replacing a car thermostat ranges from $110 to $700, depending on the thermostat type and your vehicle. 

This includes: 

• Parts cost: $10 to $400
• Labor cost: $100 to $300

B. Factors Affecting Cost

The following elements can affect your final car thermostat replacement costs:

• Vehicle make and model: Luxury vehicles, with modern engines and complex cooling systems, require specialized and expensive parts. This can increase your total bill.

• Location: Mechanics in urban areas typically charge more for thermostat installation than those in smaller towns or rural locations.

• Thermostat type: The kind of car thermostat you choose can impact your bill:
  • A mechanical or manual thermostat, common in older vehicles, is the most affordable option.
  • An electronic thermostat, a digitally controlled system used in modern engines, is significantly costlier than a manual thermostat.
  • A variable thermostat offers the highest level of temperature control and is the most expensive to replace.

• OEM vs. aftermarket parts: Original equipment manufacturer (OEM) parts are more expensive but offer better performance compared to aftermarket ones.

• Additional repairs: If your thermostat issue coincides with other cooling system failures, like a damaged radiator or water pump, the overall repair expenses can increase. For example, the average cost of swapping out a bad radiator ranges from $200 to $1,200.

Car Thermostat Replacement: Step-by-Step Process

Although a thermostat installation might seem simple, it’s not a DIY job. An incorrectly installed thermostat can lead to overheating, engine damage, and costly repairs.

A qualified auto repair mechanic will not only replace the existing thermostat correctly but also inspect the entire cooling system. Since a thermostat problem can lead to coolant leaks or overheating damage, identifying these problems early helps avoid unnecessary engine wear. 

But if you still wish to know, here’s how a mechanic will proceed:

• Wait for the engine to cool completely to avoid burns.

• Pull trouble codes from the vehicle’s computer and run diagnostics to identify related electrical or wiring faults that may cause incorrect coolant temperature readings.

• Check the engine temperature sensor and verify the thermostat opening temperature. If overheating occurred, the mechanic would take note of this, as this could have caused hidden damage beyond just a failed thermostat.

• Remove the radiator cap and position a drip pan under the drain valve. Next, they’ll open the valve and drain the engine coolant.

• Remove the hose clamp, disconnect the radiator hose, and unbolt the thermostat housing to access the old thermostat.

• Uninstall the old thermostat and the current thermostat gasket.

• Clean the thermostat housing and engine-side sealing surfaces to remove residue that may cause leaks.

• Reinstall the replacement thermostat with the correct heat rating, ensuring proper alignment (the spring side faces toward the engine). They’ll also install a new thermostat gasket for a leak-free seal.

• Bolt the thermostat housing back as per the manufacturer’s torque specifications. Then, reconnect the radiator hose and hose clamp.

• Refill the system with engine coolant, topping off with fresh coolant if any spillage occurred during the process; then reinstall the radiator cap.
  
  NOTE: If the fluid is dirty or degraded, they’ll replace it with fresh coolant. They’ll also ensure the fluid in the coolant reservoir is at the correct level.

• Run the engine for 10 minutes (keeping an eye on the coolant level) to release trapped air from the system.

Is it Worth Replacing a Car Thermostat?

Yes, absolutely.

A bad thermostat can prevent the coolant from reaching its correct thermostat opening temperature, causing the engine to warm up too slowly or overheat. Continued overheating can lead to accelerated engine wear or a warped cylinder head.

Although a car thermostat is not a part of the air conditioning system, it can still indirectly affect the cabin heating system or overall HVAC system operation.

A faulty thermostat can also create excess pressure in the cooling system if coolant can’t circulate properly. This pressure may damage the radiator and cause a coolant leak.

So, get technical support from a professional as soon as you suspect a bad thermostat to prevent severe engine damage and costly repairs.

9 Key Signs You Need a Car Thermostat Replacement

Replace your current thermostat if you notice the following symptoms:

1. An illuminated check engine light (A scan tool diagnosis can confirm if this warning is directly linked to a thermostat issue.)
2. An overheating warning message on the dashboard.
3. The temperature gauge needle moves up and down between hot and normal while driving.
4. The cabin heating system only blows cold air even after the engine has been running for a while. This becomes more noticeable in cooler temperatures.
5. The temperature gauge needle stays near the “cold” mark for longer than usual, even after driving for several minutes.
6. Gurgling noises from under the hood.
7. The engine idles higher than usual, especially during warm-up.
8. Green, pink, or orange liquid under the car, which indicates a coolant reservoir leak
9. Reduced fuel economy.

What Causes a Car Thermostat to Fail?

A car thermostat regulates engine temperature by staying closed while the engine warms up. Once it reaches the optimal operating temperature, it opens to allow coolant to flow through the radiator.

However, the device can wear out over time. A thermostat problem can occur in one of two ways:

• Stuck closed: The thermostat fails to open, blocking coolant flow and causing the engine to overheat.

• Stuck open: The thermostat remains open, preventing the engine from reaching proper operating temperature.

Common causes for this include:

• Constant heating and cooling cycles caused by fluctuating coolant temperature weaken internal components.

• Using incorrect coolant, allowing the coolant level to run low, or neglecting fluid changes can damage the thermostat.

• Faulty wiring to the engine temperature sensor may send incorrect signals to the vehicle’s computer and disrupt thermostat operation.

• An incorrectly installed thermostat may prevent the component from opening at the correct temperature, resulting in excess heat.

How Long Does a Car Thermostat Last?

A car thermostat typically lasts around 100,000 miles or up to 10 years.

However, frequent stop-and-go driving, extreme heat, or heavy engine use can put additional strain on the thermostat and shorten its life. 

How to Save Money on Your Thermostat Replacement

You can try out the following tips to cut costs while replacing your faulty thermostat:

• Compare estimates for car thermostat replacement cost from a few reputable shops.

• Use a quality aftermarket replacement thermostat that costs less and works adequately.

• Bundle repairs to save money. If you’re scheduling an AC repair or replacing a water pump, getting a new thermostat at the same time can help reduce overall labor costs.

How to Prolong Your Thermostat’s Life

Here are some ways to keep your thermostat in top shape:

• Flush the engine coolant every 2 to 3 years, or approximately every 60,000 miles. Always use the manufacturer-recommended variety.

• Pay attention to irregular temperature changes to catch thermostat problems early.

• Have your cooling system inspected annually.