How to Deal With Oil in Your Radiator

radiator cap, oil in your radiatorYou’ve got oil in your radiator?  Is it supposed to be there? How did it get there?  All great questions if your friend just asked you how to deal with oil in their radiator because you know it definitely is not supposed to be there.

Your radiator is supposed to contain coolant to help keep your engine cool because an overheating engine can cause a lot of damage.  Coolant is made up mostly of 2 things, water, and glycol.  Water is chosen because it is great at transferring heat. In fact, water is almost 4 times better at transfer heat than engine oil is!  The glycol is in your coolant, in various forms depending on what type of coolant your vehicle uses, keeps things from freezing in the winter.

Since water is so much better at transferring heat than oil is, it’s important to remove any oil from your cooling system ASAP!

How do You Know if You Have Oil in Your Radiator?

Pop the cap! 

When your car is completely cooled down of coarse, simply opening the radiator cap or cap on your coolant reservoir will quickly tell you if you have any oil in your system.  Since oil is lighter than water most of the oil in your cooling system will float to the top of your radiator or coolant overflow tank. If you see an oil slick floating on your coolant it’s important to clean out your cooling system to make sure your engine doesn’t overheat.

Flushing your cooling system is a pretty easy DIY project so you should consider tackling it yourself.  If you’ve got oil in your radiator you need more than just a garden hose to clean your cooling system.  BlueDevil Radiator Flush and Oil Degreaser is a 3-in-1 cooling system cleaner that will flush your radiator, degrease the system and removes any rust build-up to restore your cooling system to its full potential.

If you’re wondering how easy BlueDevil radiator flush and oil degreaser is to use, check out this quick how-to video so you can be sure you’re ready to get the job done.

You can pick up BlueDevil Radiator Flush and Oil Degreaser 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

Pictures Provided By:

radiator_cap.jpg – By Zenstock – Licensed by Getty Images – Original Link


6 responses to “How to Deal With Oil in Your Radiator

    1. Gerard-

      Unfortunately, we do not manufacture a product intended to stop oil from getting into the radiator. A hard part repair may be your best option.

      Thank you!


      1. So, the head gasket repair you sell only stops coolant from getting into the oil but not oil getting into the coolant? You guys also sell a product called oil leak stop. I assume that wouldn’t fix a leak traveling to the coolant area of the engine? If this is the case then I just wasted a bunch of money.

        1. Joe-

          You are correct, we do not manufacture a product intended to stop oil from getting into the cooling system. The BlueDevil Head Gasket Sealer is only intended for water/coolant leaks and the Oil Stop Leak would be intended to treat leaking rubber seals/gaskets. Unfortunately, there isn’t a product on the market that will seal a head gasket that is leaking oil into the radiator. Please contact our technical support line at 888-863-0426 so that we may assist you in getting the warranty on the product.

          Thank you!


  1. How does oil get into the radiator in the first place? I have the same problem. Could it be that it was due too much engine oil which was even causing my car to smoke. I had to drain some out yeaterday and the smoking stopped but this morning I noticed oil in the radiator.

    1. Phil-

      Usually, oil getting into the radiator would indicate a blown head gasket. Oil is leaking into the water jacket and making its way through the cooling system into the radiator. Unfortunately, a hard part repair may be your best option.

      Thank you!


Leave a Reply

Your email address will not be published. Required fields are marked *