Sealant Failure

• The most common problem experienced with radiator sealants is their failure to work properly. When using a radiator sealant, the car owner should carefully read and follow all instructions. Many radiator sealants come with a money-back guarantee. The receipt and sealant container should be retained in case the sealant fails to work.
  
  

Temporary Fix

• Many radiator sealants will only provide a temporary fix to the leak. Many leaks occur due to holes caused by corrosion of the radiator material. While the sealant may plug the leak, the material around the leak is still weak and will likely develop another hole.
  
  

Expense

• While the cost of radiator sealants vary, they are typically relatively inexpensive. However, more permanent and reliable repairs of radiators (such as soldering and epoxy) are also inexpensive and will typically have longer lasting results. Badly damaged or corroded radiators can be replaced inexpensively with a used radiator.