HELP! thermostat bolthead stripped

[Snoopyusa5]

I tried to remove the thermostat housing but the bolt would not budge and now is starting to round out. How can I get it out so we can change it? I know the thermostat is leaking and I need to change it ASAP.

[perna00]

if you got a good pair of vise grips you can always eat into the bolt so you have a good grip on it; or you can always drill off the head of the bolt, remove the housing, then either use vice grips to remove the remaining thread or drill out the remaining thread then rethread the hole; or you could try an easy out

[public]

Vise grips first as stated above. If that does not work, you can center punch then drill down the center.You can then try an easy out. If that does not work. Buy a heli-coil at any good parts store and follow the directions. Pep boys usually has a good selection of sizes and a good price ($10 or so) some of the discount parts stores only have the larger sizes for sparkplugs and they get about $40.

[Three_Fingers]

OK, I just hadda do this very same thing.

Couple ways ya can do this, all involve heat:
1.) Bust the bolt head off as you try to turn it. There will be left a "stud" after ya get the thermo housing off. Use a portable MAPP gas torch ("Bernzo" torch) to heat the "stud" and the metal immediately surrounding it until ya can crank it out with vise grips. If you heated it enough-it'll almost fall out.

2.)Heat the bolt head until ya can crank it out with vise-grips, but the thermo cover will act as a heat sink-taking heat away from the bolt so you'll hafta heat that too-and if it's plastic-that's out of the question. Better to break the bolt head off and remove the cover.

Whe cranking on the bolt head or if you break it-the "stud" that's left with vice grips-make the grips VERY tight and heat things a bit and try cranking it out a LITTLE bit-then crank it back the same amount. Then heat some more and crank it out a BIT more and then back a bit more again-repeat this process until the bolt comes out(this cooks the crud outta the threads enough to eventually free it up). Try using WD40 or better yet, PB Blaster on the bolt as well if ya break it-the combo of oil and heat works wonders. (The oil burns off when ya heat it, but what the hey.-then replace any of the bolts that look beat-actually-replace all of them. New ones are better quality than the ones that came out.
Be good to run a battery terminal cleaner (pointy end) brush into each hole and lube with WD40 or Blaster before putting the new bolts in.