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LONGHAIR · 12-18-2005, 06:55 AM

I always drill a small (say 1/8") hole in the rim of the thermostat, away from the sealing area of course. Then install it with that hole toward the front of the engine. This puts the hole in the highest place. This little hole will allow any air that could be trapped below it to bleed to the upper hose and back to the radiator. It is not significant as far as affecting overall flow/cooling, but it will stop the air pocket problem. Plus you don't have to wait for the engine to release this trapped air, and you can be sure that it is full.

The problem with trapped air is that the coolant doesn't touch the thermostat and therefore it doesn't open or it does so very late.

12-18-2005, 06:55 AM	#6
LONGHAIR just can't cover up my redneck Join Date: May 2004 Location: Columbus OH Posts: 11,414	Re: Stuck Thermostat? I always drill a small (say 1/8") hole in the rim of the thermostat, away from the sealing area of course. Then install it with that hole toward the front of the engine. This puts the hole in the highest place. This little hole will allow any air that could be trapped below it to bleed to the upper hose and back to the radiator. It is not significant as far as affecting overall flow/cooling, but it will stop the air pocket problem. Plus you don't have to wait for the engine to release this trapped air, and you can be sure that it is full. The problem with trapped air is that the coolant doesn't touch the thermostat and therefore it doesn't open or it does so very late.