A Car Thermostat Job Costs $213 to $592 in 2026

1. On six of our own 2026 estimates, a car thermostat job came to $213 to $592 with parts, coolant and labor.
2. A plain thermostat ran $213 to $316. Jobs where the whole housing had to go ran $389 to $592.
3. The thermostat itself is cheap. Ours cost $26 to $42. The housing and the hours set the price.
4. Kelley Blue Book lists an average of $661 to $747. RepairPal puts a housing job at $613 to $716.
5. Done during a water pump and timing job, a thermostat added just $110.20 on one of our estimates.

$213 to $592. That's what a thermostat job came to on six of our own written estimates from September and October 2026, with parts, coolant and labor together.

The low end is a small metal valve under a bolt-on cover. The high end is a plastic housing that cracked and had to be replaced as one piece.

We fix cars all over Hemet, San Jacinto and the rest of Riverside County, at the shop and in driveways. So this guide starts with our numbers, then checks them against the national figures.

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What Our 2026 Estimates Show

These are real Supercanic estimates for thermostat work. Labor is at our posted $150 an hour.

Each one is a written estimate, the price the owner saw before any work. Tax is not included. The Kia owner brought the thermostat, so that ticket shows coolant only. The Focus also needed a heater hose, which we left out because it is a separate repair.

Thermostat or Housing Is Where the Price Splits

Look at the chart. The three plain jobs sit together. The three housing jobs sit well above them.

On many older engines, the thermostat is a small valve that sits under a metal cover. A few bolts, a gasket and a coolant refill. That is a one to one and a half hour job on our estimates.

Newer engines often build the thermostat into a plastic housing. The housing is sold as one part. When the plastic cracks or warps, the whole thing gets replaced, and it tends to sit deeper in the engine. Our housing jobs took two to two and a half hours.

Plastic is the weak spot. Dorman, which sells a replacement for some Chrysler and Dodge vehicles, says the factory plastic part gets brittle with age and cracks.

Not every leak means a new housing, though. RepairPal says a leak usually comes from a crack or from a failed seal where the housing meets the engine. If a housing with a rubber seal is not warped, only the seal may need to be replaced. Ask your shop which one you have before you pay for the bigger part.

Why Our Numbers Run Lower Than the National Figures

Kelley Blue Book lists an average thermostat job at $661 to $747. Every one of our six estimates came in under that.

For a housing job, RepairPal lists $613 to $716 as of its September 3, 2026 update. It splits that into $202 to $296 for labor and $411 to $419 for parts.

Our labor on housing jobs was $300 to $375, a bit above RepairPal's. The big gap is parts. Our housing parts with coolant ran $89 to $217. That's about half of RepairPal's parts figure, or less.

So when you get a quote near $700, ask for the parts on their own line. The housing price tells you most of what you need to know.

An independent mechanic site, Samarins, puts a thermostat job at $150 to $370 on an average car. Our plain jobs fit inside that range.

Cheaper When It Rides Along

The best time to replace a thermostat is when the parts around it are already off.

On a 2010 Ford Ranger timing chain estimate, the water pump and thermostat were coming off anyway. The estimate added half an hour and a $35.20 thermostat. That's $110.20 for a part that would cost about twice that on its own.

On a 2005 Hyundai XG timing belt estimate, the thermostat and gasket rode along for $38.10 in parts and no added labor line.

It doesn't always work out that way. On a 2019 Chevy Silverado radiator estimate, the thermostat still carried its own one and a half hours. Being nearby isn't the same as being in the way.

Samarins notes that a thermostat is often done with the water pump when the two share an area. If your shop is in there for a pump, a timing job or a radiator, ask what it adds to swap the thermostat too.

Signs the Thermostat Is the Problem

A thermostat fails in one of two ways. Each one looks different.

• Stuck closed. Coolant can't reach the radiator. The engine overheats, sometimes fast. Pull over and shut it off. Our overheating guide walks you through the next five minutes.
• Stuck open. The engine runs cold. The gauge sits low, the heater blows lukewarm, and mileage drops. The check engine light may come on with a code like P0128.

Samarins gives a normal running range of 194 to 221 degrees Fahrenheit. It also warns that slow warm ups can be normal. Some newer, fuel efficient cars take 20 to 25 minutes of driving before the heat feels good.

A mechanic can test it without guessing. One way is to watch engine temperature on a scan tool while checking the upper and lower radiator hoses with an infrared thermometer. If the lower hose warms right after a cold start, the thermostat is likely stuck open. If it stays cool with the engine hot, it may be stuck closed. Our check engine light guide covers what to do when the light comes on.

One warning. If the engine got very hot, a thermostat may not be the whole story. On a 2019 Honda Civic Si estimate, we wrote a separate line to pressure test the system, run a block test and do a leak down test before quoting a head gasket. Testing first costs less than guessing.

Doing It Yourself

On an engine where the thermostat sits up top under a metal cover, this is a fair DIY job. The part ran $26 to $42 on our estimates. A housing assembly ran $57 to $121.

• Wait for the engine to cool. Hot coolant is under pressure and can burn you.
• Note which way the old one faces. A thermostat put in backward won't work right.
• Use the coolant your car calls for. The type is in your owner's manual.
• Bleed the air out. Samarins says the system has to be refilled and bled. Air left inside can give you poor heat at idle. Our Focus estimate had its own half hour for a vacuum fill.
• Go easy on plastic. Dorman warns that overtightening the bleeder valve can cause leaks.

When you're done, let it warm up. The fans should come on, and the heater should blow hot at idle.

What a Fair Estimate Looks Like

In California, a shop has to give you a written estimate before it makes any repairs. It can't charge more than that estimate without your OK. The Los Angeles County consumer office spells that out, and the Bureau of Automotive Repair takes complaints at (800) 952-5210.

A good thermostat estimate shows four things.

• Whether it's the thermostat alone or the whole housing.
• The labor hours and the rate.
• How much coolant, and what type.
• Whether bleeding the air and a leak check are included.

To compare, see what our cooling system repair covers, or book diagnostics first if you're not sure the thermostat is the cause.

Quick Hits

How much does it cost to replace a thermostat in a car?

On our 2026 estimates, $213 to $316 for a plain thermostat and $389 to $592 when the whole housing was replaced. Kelley Blue Book lists an average of $661 to $747.

Should I drive my car with a bad thermostat?

Not if it's overheating. A thermostat stuck closed can cook the engine. Stuck open is less urgent, but the engine runs cold, the heater is weak and mileage drops, so get it fixed soon.

How do I know if my car thermostat is bad?

The engine overheats, or it runs cold with weak heat. A check engine code like P0128 is another sign. A mechanic can confirm it with a scan tool and the radiator hose temperatures.

What does a thermostat do in a car?

It's a valve that keeps coolant away from the radiator until the engine warms up. Then it opens to hold the engine in its normal range, about 194 to 221 degrees Fahrenheit.

Should I replace the thermostat housing too?

Only if it's cracked, warped or leaking. On many newer engines the thermostat comes built into the housing, so they get replaced together. If a sealed housing isn't warped, a new seal may be enough.

Should I replace the thermostat with the water pump?

Often, yes, when they sit close together. On one of our timing chain estimates, adding the thermostat to the water pump job cost $110.20.

What We Read

Kelley Blue Book, Car Thermostat Replacement Costs
RepairPal, Thermostat Housing Replacement Cost Estimate September 3, 2026
Samarins, Thermostat. How It Works, Symptoms, Problems, Testing October 2, 2022
Dorman 902-3035HP Thermostat Housing Assembly, product description
Los Angeles County Department of Consumer and Business Affairs, Car Repairs March 4, 2024
Supercanic Shop Desk estimates with thermostat work, August 28 to October 25, 2026