What Causes a Radiator to Leak?

radiator, what causes a radiator to leakIf you’re wondering what causes a radiator to leak then you’ve probably already have a leak and it’s too late for preventative measures.  If replacing the radiator in your vehicle doesn’t make sense consider using BlueDevil Radiator and Block Sealer to seal the leak in your radiator and keep your vehicle on the road!

With some repair ideas out of the way, let’s get to talking about what causes a radiator leak:

  1. Overpressure
  2. Impact
  3. Corrosion
  4. Normal heat cycling


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.


Impact is the most common cause of radiator leaks in cars today.  Anything from a head-on collision to a small rock kicked up on the highway.  Most impacts are unavoidable so all you can is inspect your radiator, especially where it can be seen through your grill.


Corrosion can cause leaks as it can in any system but when it comes to what causes a radiator to leak its internal corrosion.  Most radiators today are made from plastic and aluminum neither of which corrode easily. Unfortunately, old or poorly mixed antifreeze can cause corrosion in your radiator so it’s important to regularly flush your radiator.

Normal Heating Cycles

Heating and cooling cycles will fatigue any material and over time it will weaken it and cause cracking.  The aluminum and plastic in the radiator is no different and often times the plastic end tanks of your radiator are the parts to fail first.  If the leaks are small you can use Blue Devil Radiator and Block Sealer but if they are too large the only option you may have is to replace the radiator.

You can 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

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radiator.jpg – by 524906500 – Licensed by Getty Images – Original Link