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1966 Coupe. 302.

EMP Stewart High Performance Thermostats 301

I just replaced my thermostat. This one had 3 gaps to be placed at the 12:00 position. It just hit me that I didn’t ch3ck the position of these gaps. So it may be placed correctly or not. How important is the position? Do I need to open it up and make sure of the position?

Thank you

Allen
 

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The gaps are there to help air escape so you don’t get trapped air in the system. Original thermostats did not have these. it used to be a common practice to drill a hole or two in the thermostat to help. Eventually manufacturers started including the holes in replacement thermostats. If you housing is the type with a Allen key plug on top, you can pull out the plug to help clear any air. If not you just have to work at it a bit. It helps to elevate the front of the car so any air rises up and flows into the radiator. Overall it’s not a big deal for most people.
 

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Once the thermostat opens any air will be purged out of the engine and then the hole doesn't do much. Its when you are first filling up the engine that those holes let the air vent out and the coolant in. If air is trapped behind the thermostat it might not ever open. I've had it happen to me several times at work. Your running the engine with your hand on the upper hose, waiting to feel the hot water start flowing through it (a sign the thermostat has opened).The hose will still be cold and the temperature gauge will be heading towards hot. That is because the air trapped behind the thermostat is not hot enough to open the thermostat. Then I would have to go back and take off a heater hose or a temperature sensor on the intake and bleed that air out of there. What you can do is leave the temp sender out of the intake and poor the coolant in until it reaches the level of the sending unit.That way the thermostat should be in the coolant. Or you take it apart and put it back together like it is suppose to be. It wouldn't take you very long to fix it. Even if it didn't matter it would still bug me I had screwed up and I would have to go back in and make it right.
 
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