HELP!!!! rounded bolt!!!

[fisherbear]

I'm trying to replace a thermostat and it has 2 10mm bolts holding it in.... I got one of them out no problem but the other one is rounded out bad... I've tried 4 different types of 10mm sockets, 2 different types of 10mm wrenches, adjustable pliers and I even went to autozone and got a set of the special grip tite sockets that are supposed to grab the bolt on the side and not on the edges... that one just spun around... I got a 3/8 socket and smashed it in with a hammer to see if that would get a better grip but that didn't do anything but spin freely...

my truck isn't overheating but when driving it yesterday it went well above the half mark to about 70% which is quite unusual for my truck (its usually around the 25%-30% mark) so it's more of a preventative thing... my 2 options are to screw in the good bolt and put in fresh coolant and pray it doesn't over heat in the texas sun.... or get this bolt out somehow... I'm sure there is some rust damage to the threads... I had the thermostat changed maybe 5 years ago... opinions? thoughts... thanks :?:

 

[drsvox]

sometimes when I can't back out a bolt or screw I'll try to tighten it first to break the lock...not sure that will work in your case; sounds like the head is rounded pretty bad (but it might be worth trying).

barring that you've got a few options: the best might be to bring it to a shop and have them back it out for you.

if you weld or have access to a friend who welds, next best would be to drill a center hole into the rounded bolt, then weld on a nut (filling the hole in the nut and the bolt). let it cool, then carefully back it out.

last, you can try a back out drill bit. some are tapered screws, others are reverse drill bits. you have to drill a pilot hole first, then drill with a back out bit. for me, this is rather difficult, and you risk damaging either the housing or block (especially w/ a 10mm bolt).

 

[Tractor Dan]

If the head is still there and it sounds like it is. Take a dremel and cut a slot in the head like a straight screw head. Then take a screw driver bit on a ratchet and see if it will break loose. Just be sure to plug the inlet of the thermostat housing with a rag or tape it off so metal shavings don't get in. That's another thought. Hopefully one of these works for you. It may be my idea won't work with the space.

 

[black_demon69]

could also use a propane torch to heat bolt or housing then vise grip it out or slot like suggested above, and if that doesn't work cut head off remove t stat housing and heat whats left of bolt and turn with vise grips.

 

[fisherbear]

I'm going to try the Irwin bolt extractor tomorrow... I hope it works much better than everything else I've tried so far...

 

[Twister]

Get some of these. I have used them to remove exhaust nuts that have completely rounded off and they worked great. Make sure you spray some penetrating lube on the bolt and let it sit for a little but for extra help.

http://www.amazon.com/gp/aw/d/B0000CCXVZ?tag=959media-20

 

[black_demon69]

when you install new bolts use antiseize and they will com out easily the next time.

btw what engine and can you take pic?

 

[freedom5]

I'm trying to replace a thermostat and it has 2 10mm bolts holding it in.... I got one of them out no problem but the other one is rounded out bad... I've tried 4 different types of 10mm sockets, 2 different types of 10mm wrenches, adjustable pliers and I even went to autozone and got a set of the special grip tite sockets that are supposed to grab the bolt on the side and not on the edges... that one just spun around... I got a 3/8 socket and smashed it in with a hammer to see if that would get a better grip but that didn't do anything but spin freely...

my truck isn't overheating but when driving it yesterday it went well above the half mark to about 70% which is quite unusual for my truck (its usually around the 25%-30% mark) so it's more of a preventative thing... my 2 options are to screw in the good bolt and put in fresh coolant and pray it doesn't over heat in the texas sun.... or get this bolt out somehow... I'm sure there is some rust damage to the threads... I had the thermostat changed maybe 5 years ago... opinions? thoughts... thanks :?:

You might try soaking it with PB Blaster prior to using the Irwin tool. I haven't had any experience with Irwin but you will probably have to remove the radiator to drill a hole in the bolt to uses any extractor. There's not enough room to get a drill in between the radiator and bolt head and you certainly don't want to drill the hole at an angle. Be sure and center punch the head before you drill.

 

[alwaysFlOoReD]

You might try soaking it with PB Blaster prior to using the Irwin tool. I haven't had any experience with Irwin but you will probably have to remove the radiator to drill a hole in the bolt to uses any extractor. There's not enough room to get a drill in between the radiator and bolt head and you certainly don't want to drill the hole at an angle. Be sure and center punch the head before you drill.

The extractors they are talking about grip the outside of the bolt head. They can work. I ended up drilling out and tapping on an exhaust bolt that they wouldn't work on.
This is the set I have;
http://www.sears.com/craftsman-10-pc-damaged-bolt-nut-remover-set-low/p-00952166000P

Good luck,

Richard

 

[Spott]

If all else fails, cut/grind the head off the bolt and work on the shank later. Use lots of penetrating oil on the shank, and try a pair of nuts, or vise-grips, or something.