How do you fix a leaking radiator petcock?

Petcock Fix

Here are answers and opinions from FAQ Farmers:
  • First off, don't open a Durango petcock. If you already did there are replacement ones available after market. Another solution is to get it dry and silicone it in place, let it dry (24 hours), fill your system back up.
  • Plastic petcocks can be replaced by first removing the radiator from the vehicle. Now remove the stripped drain plug, then use an ice pick to remove the retaining clip inside the hole that the plug screws into (this is the part that usually fails). New plugs can be purchased at the dealer or NAPA....Next, unscrew the retainer clip from the new plug. Install the retainer clip and make sure it locks into place....be sure the retainer clip fits properly in the hole as each brand is different. In cases where the radiator is not the original, you may have to get a replacement drain plug from the aftermarket dealer that sells that brand radiator. Finally, screw the new plug into the hole using vaseline on the rubber gasket to help it seat tightly without having to overtighten the petcock. Better to leave it snug and then pressure test it for leaks and tighten it if necessary than to overtighten it. The stress from overtightening it may not damage it right away....it will fail when it gets hot a few times and under pressure....then it will dump all the coolant in a hurry. Something else to think about...usually this failure comes from overtightening or coolant contamination causing the plastic components to weaken and fail. Flush cooling system and check for oil or other contaminants.

If these petcocks are opened properly, there should not be a problem. Too many people just yank and twist on them causing unnecessary damage. If it does come out or leak, good old Teflon pipe tape works just finer.