How Do You "Drill" A T-stat
Thread Starter
Senior Member
True Car Nut
Joined: Jan 2004
Posts: 4,328
Likes: 1
From: Lakeville, MN

I see and hear a lot about people having a 180 "drilled" t-stat. By that what do they mean? I'm guessing its just that, drilling holes in it. If thats the case how do you do it without breaking it?
http://www.zzperformance.com/article...d90601b745c321
http://www.zzperformance.com/products1.php?id=231
Tech article and a link to a photo of one. You need to drill the outside of the t-stat.
http://www.zzperformance.com/products1.php?id=231
Tech article and a link to a photo of one. You need to drill the outside of the t-stat.
Senior Member
Posts like a Corvette
Joined: Jul 2004
Posts: 1,256
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From: Bolingbrook, IL Location: Clarkston, MI

I think you are just over thinking this - you just drill 2 holes in the flange of the T-Stat. I don't know what you could break in this process.
You need to drill so the rubber seal doesn't block them. And those 2 holes are WAY too big. I'd say that Tstat would be for track use only.
http://www.bonnevilleclub.com/forum/...ill+thermostat
http://www.bonnevilleclub.com/forum/...ill+thermostat
Thread Starter
Senior Member
True Car Nut
Joined: Jan 2004
Posts: 4,328
Likes: 1
From: Lakeville, MN

I see. What are the adverse affects of having holes that are to big? I live in an extreme climate. Ranges from -20*F to 100*F. I am going to put on a 3.5" pulley. Heading into the warm season the 180 drilled is a must. But in winter should I switch back to the stock 195 even with the pulley?
i had a 180 on mine with stock pulley and car barely got warm. it took about 35 minutes to get it to running temp. i switched back to 195 late in november and it will probably stay in there. the need has yet to pass 200, even on a warm night with no ice at the track.
Yeah, those holes look to be AT LEAST 1/4". I wouldn't suggest more than 2 or MAYBE 3 (with mods that are creating more heat) 1/8" holes (which is what I found to be excellent in my 1998 SSE last September with temps in the low 80**).


