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post #1 of (permalink) Old 11-08-1999, 12:20 PM
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Thermostat hole?

I've heard some talk about drilling a hole in the thermostat. Why, and how does it help.

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post #2 of (permalink) Old 11-08-1999, 02:30 PM
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Re: Thermostat hole?

[img]/wwwthreads_images/icons/laugh.gif[/img] As they say in Washington: "Senator....I'm glad you asked me that!" [img]/wwwthreads_images/icons/wink.gif[/img] The reason for the hole is to let the air blow by the thermostat as you fill the engine the first time, AND also to let a tiny bit of water squirt by and make sure that an air pocket isn't forming under the thermmy which will NOT open it on temperature rise.[img]/wwwthreads_images/icons/frown.gif[/img] needs liquid to touch the bulb.[img]/wwwthreads_images/icons/cool.gif[/img] In some engines LIKE A SMALL BLOCK CHEVY...the engineers were asleep and no provision was made for getting the air out. I KNOW...I KNOW...the thermostat has a tiny dent in the seat for that purpose, but it soon plugs up. The temp sometimes will rise WAY up, then drop like a rock in the SB Chevys when the thermostat FINALLY opens. I got tired of that in my 350 GMC and drilled a lead-pencil sized hole in the thermostat plate....the wide-open flat area.[img]/wwwthreads_images/icons/smile.gif[/img] After that it was like being behind a REAL engine,[img]/wwwthreads_images/icons/laugh.gif[/img] like a Mopar. Heh heh. Drill your thermmy.[img]/wwwthreads_images/icons/crazy.gif[/img]'ll be doing your engine a favor.[img]/wwwthreads_images/icons/laugh.gif[/img]

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post #3 of (permalink) Old 11-08-1999, 03:15 PM
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Re: Thermostat hole?

some performance stats have the hole drilled in them for you (try mr gasket). Dave hit it right on the head with the need for a bleed. a lot of import stats use a small hole with a small valve to do the same thing.


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