Radiator Cap Replacement Cost Estimate

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John Davis
Expert Automotive Writer
Reviewed by Kathleen Flear, Director of Content
Edited by Jessica Barrett, Senior Car & Insurance Editor

How much does it cost to replace a radiator cap?

Your exact radiator cap replacement cost will depend heavily on your vehicle type and location. But the average cost is around $10-$30.
How long does it take to replace a radiator cap? Replacing a radiator cap is quick and easy, and a trained technician should be able to complete the service in under 10 minutes. Keep in mind, however, that many repair shops charge by the hour or half-hour at a minimum—meaning you may have to pay for 30 minutes of labor even if the procedure only takes 10 minutes. 

How did we estimate these prices?

Jerry's experts researched and collected data from 2500+ real repair shops in all 50 states in the US, including everything from the total cost of repair services to the hourly labor cost for mechanic labor in each shop. We combined that data with our expert database of hundreds of real repair jobs, thousands of real cars, millions of real car part prices in order to best estimate the cost of each repair service. Our labor cost estimate is calculated by taking the average hourly labor rate for a certified mechanic in the US, times the number of hours it takes on average to complete a repair. We recommend you compare your local shops with Jerry and contact those shops directly to get final pricing for your vehicle.

What parts do I need for my radiator cap replacement?

You should check your vehicle repair guide and
owner’s manual
for detailed information. But here’s a general overview of the parts you may need during a radiator cap replacement:
  • Radiator cap: The primary part you’ll need to replace is the radiator cap itself. Depending on your car and the type of cap you purchase, you shouldn’t have to spend more than $5 to $25 for a replacement. 
  • Coolant: You may not need to purchase any coolant when you replace your radiator cap. But if the faulty cap caused a coolant leak, you’ll probably need to top off your coolant expansion tank or reservoir. One-gallon jugs of coolant typically cost between $10 and $30.
Some reputable brands we recommend for reliable radiator caps are Stant, Motorad, and Gates. Meanwhile, some of the the best coolant brands include Prestone, Zerex, and Peak. You can typically find these brands from retailers such as Amazon, Walmart, AutoZone, Advance Auto Parts, and O'Reilly Auto Parts, both online and in-store. However, like price, recommended brands may also vary depending on your vehicle's specific year, make, and model.
If you want OEM parts, you’ll have to buy them from your local dealership or authorized parts retailer. You can find aftermarket parts at auto parts stores—like AutoZone, Advance Auto Parts, and O'Reilly Auto Parts—or online retailers like Amazon or Walmart.
When it comes to automotive replacement parts, most experts recommend opting for original equipment manufacturer (OEM) parts whenever possible. And OEM parts are especially preferable for owners of newer vehicles due to the manufacturer’s warranty that comes with them. 
OEM parts are designed specifically to fit your car. They’re high quality and are typically considered more reliable. 
Aftermarket parts, on the other hand, are produced by third-party manufacturers. They come in a wide range of options, from budget to premium quality. While aftermarket parts may be lower quality than OEM, they can still be an excellent choice—just remember to confirm the fit for your vehicle by checking the part number.

Where can I get my radiator cap replaced?

It can be difficult to find an honest and reliable mechanic. Luckily, Jerry's
can help you compare hourly rates, repair estimates, and customer reviews from more than 2,500 repair shops around the country.
Jerry's GarageGuard™ uses real hourly rates from local shops to give you fair price estimates for common repairs and services. Use GarageGuard™ to learn about diagnostic fees, budget for upcoming maintenance, and find the shops near you with the best reviews.
Below you can view some of our vetted shops—and don’t forget to download the app to find quality repair services near you. 
187 Reviews
106 St Tire & Wheel
106-01 Northern Blvd, Manhattan, NY
Radiator Cap Expansion Tank Cap
Fair Cost Estimate for This Shop
(Parts - $7, Labor - $29)
Shop Diagnostic Fee
(Included in service charges)
195 Reviews
RepairSmith - San Francisco Bay Area

Radiator Cap Expansion Tank Cap
Fair Cost Estimate for This Shop
(Parts - $7, Labor - $34)
173 Reviews
Fresno Tire Company
6632 N Blackstone Ave B, Fresno, CA
Radiator Cap Expansion Tank Cap
Fair Cost Estimate for This Shop
(Parts - $7, Labor - $33)
Shop Diagnostic Fee
(Included in service charges)
115 Reviews
On The Go Tires
(Mobile repair service), Fort Myers, FL
Radiator Cap Expansion Tank Cap
Fair Cost Estimate for This Shop
(Parts - $7, Labor - $20)
Shop Diagnostic Fee
(Included in service charges)

How did we vet these shops?

Jerry experts researched 2500+ real repair shops across the US. We talked to real shop customers, and analyzed both real shop pricing data and thousands of real customer reviews from each shop to verify them individually. We do not partner with the shops listed above, and our analysis is always unbiased.

How will a mechanic replace my radiator cap?

These are the steps your mechanic will follow to replace your radiator cap:
  • Allow the engine to cool completely
  • Open the hood and locate the radiator cap near the top of the grille
  • Place a rag over the cap to protect against coolant splashes
  • Push down on the cap and turn it to the left
  • Remove the old cap
  • Check to make sure the new cap matches the new one
  • Install the new radiator cap by pushing it down and screwing it to the right
  • If necessary, top off the fluid in the coolant recovery tank or reservoir

What happens if I don’t replace my radiator cap?

If you don’t replace a faulty radiator cap, you risk developing these problems:
  • Coolant leaks: If the radiator cap doesn’t seal the cooling system properly, you may develop coolant leaks. This can lead to a loss of coolant, engine overheating, and serious damage.
  • Air pockets in the system: A faulty radiator cap can allow air into the cooling system. This can result in airlocks that prevent the coolant from circulating through the engine, leading to overheating and engine damage.
  • Excessive or insufficient pressure: One of the radiator cap’s primary jobs is to maintain the cooling system pressure. If the cap fails, the pressure can drop too low or rise too high. This can result in a variety of problems, including collapsed hoses and blown gaskets. 
  • Coolant contamination: If the cap doesn’t seal the radiator correctly, debris and contaminants may enter the coolant. This can lead to engine damage and affect your car’s performance.
  • Reduced fuel efficiency: If a faulty radiator cap causes your engine to overheat, you may notice your fuel economy plummets. 

What is a radiator cap?

The radiator cap seals your car’s engine cooling system and maintains its pressure. 
Its primary purpose is to maintain the system pressure, which raises the engine coolant’s boiling point and prevents overheating. Additionally, the cap allows excess pressure and coolant to escape into the coolant overflow tank—also known as the coolant reservoir or expansion tank. 
Remember not to confuse the radiator cap with the coolant reservoir cap or expansion tank cap. The radiator cap is a pressure-sealing cap that sits on top of the radiator or, in some vehicles, the overflow tank. The coolant reservoir cap, on the other hand, is typically a plastic cap that pops on and off, allowing you to access the filler port and add more coolant to the system. 

When should I replace the radiator cap on my car?

Since there generally isn’t a set replacement schedule for your car’s radiator cap, you should only have to replace it when it fails. Here are the most common signs of radiator cap failure:
  • Coolant leaks: One of the most common signs of a bad radiator cap is a coolant leak. If the cap can’t regulate the system pressure properly, the excess pressure can force coolant out through the path of least resistance. 
  • Engine overheating: If the radiator cap can’t maintain the proper pressure, the coolant’s boiling point may decrease. This can lead to engine overheating issues.
  • Collapsed radiator hoses: If the pressure in the cooling system drops too low, the resulting vacuum may cause your radiator hoses to collapse.
  • Coolant overflow: If the engine overheats, the coolant may boil over. If you notice steam coming from under your hood, stop driving and turn the engine off as soon as it’s safe to do so.
  • Frothy or milky coolant: In extreme cases, a faulty radiator cap can cause your engine head gasket to blow. This can result in oil mixing with the coolant, which will give it a milky appearance. 
Keep in mind: The above issues can indicate other problems with the cooling system, like a faulty thermostat or water pump. If you experience any issues with the cooling system, you should contact a professional mechanic for diagnosis. 

How often should I replace my radiator cap?

There is no universal replacement interval for radiator caps. Some experts recommend replacing them every 60,000 to 100,000 miles, while others say you should wait until the caps fail. The best thing to do is check your owner’s manual to learn whether your car’s manufacturer recommends replacing the cap as part of a maintenance plan.
Otherwise, you shouldn’t have to replace yours unless it malfunctions. Some of the most common signs that indicate a radiator cap problem include coolant leaks and an overheating engine. 

Can I replace my radiator cap myself?

Yes—replacing the radiator cap is an excellent DIY project. It requires little-to-no automotive repair experience, and even novices should have no trouble performing the service. That said, if you’re uncomfortable handling coolant or replacing the cap yourself, you should contact a trained mechanic. 


If the radiator cap goes bad, your car’s cooling system will likely be unable to maintain the proper pressure. This can lead to a variety of issues, including:
  • Coolant leaks
  • Engine overheating
  • Engine damage
The most common way to test a radiator cap is to perform a pressure test. You can do this with a cooling system pressure test kit and by following these steps:
  • Remove the radiator cap
  • Attach the cap to the test kit’s air pump
  • Use the pump’s lever to apply the specified amount of pressure to the cap
  • Observe the pressure gauge for five minutes
  • If the pressure drops rapidly, the cap is bad
You should avoid driving with a bad radiator cap whenever possible. While you may be able to get a few miles down the road, running your engine without the radiator cap is extremely dangerous. Without the cap, the cooling system will be unable to maintain the proper pressure, leading to engine overheating and potentially costly repairs.

Meet Our Experts

John Davis
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Car Expert
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Certified mechanic with 10+ years of experience
John Davis is an expert automotive writer and former automotive mechanic. John's work spans multiple categories, and he relishes the opportunity to research a new subject and expand his area of expertise and industry knowledge. To date, John has written more than 200 articles covering car maintenance and care, car advice, how-to guides, and more.
Prior to joining Jerry’s editorial team, John worked as a mechanic and freelance writer, creating content for clients including HotCars and SetPower.
Jessica Barrett
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Car Expert
Jessica Barrett is a senior insurance writer and editor with 10 years of experience in the automotive and travel industries. A specialist in car insurance, car loans, and car ownership, Jessica’s mission is to create comprehensive content that car owners can use to manage their costs and improve their lives. As a managing editor for a team of writers and insurance specialists, Jessica has edited over 2,000 articles for Jerry on topics ranging from local insurance shopping tips to refinancing car loans with bad credit.
Before joining Jerry as a senior content editor in 2021, Jessica created visual content for clients such as Expedia, Vivid Seats, Budget Direct Car Insurance, Angie’s List, and HomeAdvisor. Her content was published in Business Insider, Forbes, Apartment Therapy, and the BBC.
Kathleen Flear
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Car Expert
Kathleen Flear is an expert insurance writer and editor who heads up Jerry’s editorial team as director of content. Kathleen empowers drivers to make smart car ownership decisions through  best-in-class articles on insurance, loans, and maintenance. Prior to joining Jerry in 2021, Kathleen served as managing editor for a team of SEO content marketing professionals at and worked as a freelance writer and editor for a range of digital publications, including Chicago Literati magazine and Golden Words. She earned a bachelor’s degree in English language and literature from Queen’s University, and a master’s degree in creative writing and fiction from Sierra Nevada University.
*The price information provided on our car repair webpages is intended for general informational purposes only. Actual prices for car repair services may vary based on various factors, including but not limited to the make and model of your vehicle, the extent of repair required, and the prevailing market conditions. All prices for real repair shops are estimations based on our research only. Therefore, the prices listed on our webpages should not be considered as final quotes or binding offers.