jiggle pin

[cutler]

i never heard of a jiggle pin.before i read this in the forum,i put a new thermostat in the 94 camry-cost about 10 dollars,i didnt notice any jiggle pin on it. i didnt check it to see if it had a pin. there is nothing wrong with the temp. on the car,it doesnt get to the half way mark--so i guess there is no reason to take it out and check it, my question,do you think a 10 dollar thermostat would have a jiggle pin---and what kind of problem would i have,if it did have a jiggle pin and i didnt put it on top--thans for the info.---cutler

[500KCamry]

As near as I can guess the jiggle pin allows a 5sfe system to cold fill properly by letting air in the bottom rad hose escape past it. Without it, you get an air lock there until the thermostat opens. When it opens the air will pass and the overall coolant level will drop, but if the rad cap is still off, you can then top er up before the rad cap is put on. Once the rad cap is put on, then fill the overflow tank to the hot level.

Just a novice's analysis. Maybe someone else can confirm or adjust this.

[Hajoca]

500K is right,

The jiggle pin is a small wire slightly smaller put through a hole in the thermostat that will be in contact with the engine side of the water jacket, and the rad side.

In normal operation, the small hole will not do much for flow, the pin is there to add more restriction so that only air pockets/ bubbles get through.