How to Stop a Radiator Leak in a Snowmobile

A leaking snowmobile radiator can have many causes, ranging from punctures or cracks in the radiator to metal corrosion or even deep rust spots. Fortunately, a number of products exist to help stop these leaks without requiring expensive service to completely replace the radiator. Stop-leak products work by filling the damage from the inside, whereas external patching products can more directly seal the leak.


1)ย Unscrew the cap on the coolant overflow container. Fill the container with a small engine radiator stop-leak solution, following the instructions printed on the product for the specific amount to add.

2)ย Replace the cap and start the engine. Let it warm up and idle for several minutes, then check the system for leaks. Ideally, the stop-leak will have done its job and fixed the problem. If not, an external patch will be required.

3)ย Mix a generous amount of radiator epoxy by follow the instructions included with the product. Only use an epoxy specifically designed for use on small engine radiators. Use a rag to wipe any dirt or coolant off the source of the leak, then smear the epoxy over it, making sure to saturate the entire area, leaving no space for coolant to escape. Work quickly, since the epoxy will begin to harden in only a few minutes.

4)ย Wait the appropriate amount of time indicated on the product’s instructions to allow the resin to cure. When it is fully hardened, fill the coolant tank with antifreeze and start the engine to test the seal.