Thermostat does not close fully

[KevAndAndi]

I removed the thermostat and was able to blow through all three ends. The plug inside the tube I should not be able to blow through (the end that connects to the lower rad hose) does not seat properly. There's a gap along one side. This is the doohickey that folks frequently drill a hole in, to avoid air pocket problems. I just boiled the stat in an old bread pan (don't worry - my wife gave the OK to trash it) and it did open.

Is this t-stat still OK to use? Seems to me that if the purpose is to warm the engine quickly, and our car is driven only in warm weather, it won't really do any harm. Plus, the existing gap obviates the need to drill a hole - though the gap is probably equal to about five 1/8" holes.

[So Cal Mark]

as long as the engine gets to operating temp (180) and stays in that range when driving, it will be okay. If you find it drops down below about 160 at highway speeds, the engine is running too cold. The stat is intended to keep the engine at a constant temperature, that's best for efficiency and longevity

[KevAndAndi]

Thanks, Mark. At least I will be assured there will be no air pocket, which could lead to overheating.

The temperature pretty much stays around 190. It will go a tad higher, and then the fan comes on. On a cool evening, it may dip down to 180 around town.