Posts Tagged: thermostat jiggle pin

What a Thermostat Jiggle Pin Does

What the thermostat jiggle pin does and why it’s important to replace with the same kind A jiggle pin works when the engine is off to prevent air pockets from surrounding the themostat’s wax pellet. When y ou shut off the engine and there’s no longer any water pressure pushing against the thermostat, the weighted pin falls, providing a pathway for any trapped air to vent through the hole. So thermostat jiggle pin is a bleeder valve of sorts. How does air get into the cooling system? Any time you flush … Read More