What Caused Your Radiator Crack and How to Fix it 


radiator, what causes a radiator to leakIf you’ve ever cracked your radiator or are currently dealing with a leak, you might be wondering what you can do to prevent it from happening again. Before you can start addressing a solution or adapting your behavior, you need to understand what can cause a radiator to crack in the first place. From primary causes to fast-acting and cost-effective solutions, everything you need to know about diagnosing, preventing, and fixing a radiator crack can be found right here! If you’re here because you think your radiator might need replacing, BlueDevil Radiator and Block Sealer is an incredible solution for sealing leaks and restoring your radiator to its former glory. Save hundreds in repair costs by using our sealer today! 

BlueDevil Radiator and Block Sealer! 

What Can Cause a Radiator to Crack

Here are a few of the main causes of radiator cracks. Read more about each cause below. 

  1. Temperature Fluctuations 
  2. Rocks
  3. Accidents
  4. Radiator Fans
  5. Dirty Coolant
  6. Over Pressure

Temperature Fluctuations 

Your radiator has to be able to function anywhere between ambient temperature (which varies depending on where you live) to over 200 degrees! These drastic swings create thermal stress on the metal and plastic in the radiator, which can cause a radiator to crack or leak over time, regardless of how well you care for your vehicle.


Your radiator is at the front of your vehicle protected only by your vehicle’s grill. Rocks and road debris can easily find their way in through the grill and poke holes in your radiator tube and fin matrix. These leaks are often slow and will cause drips at the front of your vehicle. Small leaks like this can easily be fixed using BlueDevil Radiator and Block Sealer.


Fender benders regularly cause radiator leaks since your radiator is at the front of your vehicle.  Anything that pushes on the front of your vehicle has the chance to damage or even split the radiator core support, causing leaks in the radiator or in the coolant hoses that connect to it. If you’ve been in an accident, make sure your frame is straight before attempting to repair your radiator.

Radiator Fan

Fans can cause radiator damage in two ways.  If your radiator fan doesn’t turn on it can cause high temperatures and pressure in your system, leading to cracks. On the other hand, if your radiator fan is spinning but has a bad bearing, the wobbly fan can contact your radiator damaging the tubes and causing a leak.

Dirty Coolant

Dirty coolant can cause a radiator leak due to corrosion. If your coolant is dirty or of the wrong type it can cause pitting in the aluminum radiator or cylinder head. Since your radiator is made of thin metal small pits in the aluminum can lead to leaks. Make sure to regularly flush your radiator to ensure your coolant is not damaging your radiator.


As the antifreeze in your cooling system heats up it will expand and expanding fluids increase pressure in a closed system.  Your radiator cap is designed to release pressure at a certain point, usually between 10 and 18 PSI. If your radiator cap is malfunctioning it can cause an overpressure in your system which can damage some of the more delicate components in your radiator.  Radiator caps are usually inexpensive so consider replacing yours if you are worried about high pressures in your system.

How Long Can You Drive With a Cracked Radiator?

If you have a cracked radiator, your check engine light may not come on immediately. But if you notice an issue, you should never drive with a cracked radiator. Driving without a working radiator can cause your car to overheat, stop working altogether, or even catch on fire! Driving with a cracked radiator is simply not worth the risk. 

Cracked Radiator Cost

The price to fix a cracked radiator will vary greatly depending on the make and model of the vehicle as well as how you choose to get the radiator fixed. If you need a complete replacement and get it repaired at a shop, your costs will be much higher than a simple patch job or attempting to seal a leak with a stop leak solution. Find out more about how much your cracked radiator will cost you in our blog post titled “How Much Does it Cost to Fix a Radiator?

How to Avoid Paying for an Expensive Replacement 

Cracked Engine BlockWhat causes a radiator to crack won’t change the methods for mending the issue. Major cracks in the top of your radiator may call for replacement. However, if your issue is a minor one or replacement is too expensive, consider using BlueDevil Radiator and Block Sealer! Our sealer is trusted by industry professionals to seal the toughest leaks and cracks. The best part? It can fix your radiator without ever putting your car in the shop. Full replacement should always be a last resort. See if BlueDevil Radiator and Block Sealer can work for you! 

Fix Your Radiator! 

You can also find BlueDevil Radiator and Block Sealer, you can find it at one of your local auto parts stores like:

  • AutoZone
  • Advance Auto Parts
  • Bennett Auto Supply
  • CarQuest Auto Parts
  • NAPA Auto Parts
  • O’Reilly Auto Parts
  • Pep Boys
  • Fast Track
  • Bumper to Bumper Auto Parts Specialists
  • S&E Quick Lube Distributor
  • DYK Automotive
  • Fisher Auto Parts stores
  • Auto Plus Auto Parts stores
  • Hovis Auto & Truck Supply stores
  • Salvo Auto Parts
  • Advantage Auto Stores
  • Genuine Auto Parts stores
  • Bond Auto Parts stores
  • Tidewater Fleet Supply
  • Bumper to Bumper Auto Parts
  • Any Part Auto Parts
  • Consumer Auto Parts


BlueDevil Products can be found on Amazon.com or at AutoZone, Advance Auto Parts, O’Reilly Auto Parts, NAPA, and other major auto parts retailers.

6 responses to "What Caused Your Radiator Crack and How to Fix it "


  1. Phillip Sloan on August 28, 2020 at 2:28 am

    Are stores available on the island of Mindoro Philippines to buy products

    • BlueDevil Pro on August 28, 2020 at 8:59 am


      We currently do not have any distributors in the Philippines. However, the product may be ordered directly through our website and shipped to your residence. The shipping cost will automatically calculate at checkout after you have input your mailing address. The product may be ordered here: http://store.gobdp.com/head-gasket-sealer-38386/

      Thank you!


      • Jack S Gates on November 2, 2020 at 7:03 am

        My leak seems to be coming from the block, behind the thermostat.
        Would block sealer fix that?

        • BlueDevil Pro on November 2, 2020 at 10:11 am


          Yes, the BlueDevil Radiator & Block Sealer would be able to treat a seeping/lightly dripping block leak. Feel free to contact our technical support line at 888-863-0426 with any other questions.

          Thank you!


  2. Victor Dove on February 7, 2021 at 3:31 am

    I used Blue Devil Coolant Stop Leak to fix a leak where the top plastic tank meets the radiator, it reduced the leak, but didn’t stop it. I think that the Blue Devil Radiator & Block Sealer product might work better in this case, but I want to know if I can pour the whole Radiator & Block Sealer bottle in the radiator without flushing it?

    • BlueDevil Pro on February 8, 2021 at 9:44 am


      As long as the system is clean, it would be fine to add the BlueDevil Radiator & Block Sealer at this point. Feel free to contact our technical support line at 888-863-0426 with any other questions.

      Thank you!


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