Hey guys...I was going to replace my thermostat today (stuck open) and the previous owner stripped one of the thermostat housing Torq bolts. Is there a special tool or trick to getting it off?

 

Depends, which one? Pic please

 

In this pic it's the one in the upper right circled in red

 

I had the exact same problem, took the car to my local indie muffler shop, $10 and they loosened the bolts, I drove the car the 1 mile home,took those bolts to True Value and replaced the torx bolts with standard stainless steel hex head bolts of the same size, length and thread pitch.
Total cost was about $15 including the cost to have the shop loosen the bolts.

Replace your coolant temp sensor as long as you are in there.

 

Once you get it out I'd recommend using regular machine bolts with a hex head or paying a buck more and get stainless steel (any hardware store). I like the quirky torx but they suck if you have one that gets stuck and you really need to muscle it. Also applying some anti-seize compound will help you or the next guy if it needs to come apart again. Small packet 1.30 or so at an auto parts store.

I don't know of anything specific but there is always the old standby of using a vice grip if you can get it to cut into the head. On something stripped I will usually clamp it down hard, release it and tighten it a little more and clamp it again. Each time it cuts in a little more and then use the leverage.

You might also be able to get away with drilling off the head so that it releases the clamping torque, remove the other screw and then the housing and with the torque load removed the body of the screw might back out quite easily. It could also be seized in the hole so it's kind of 50/50.

If you can get to the bottom of the bolt applying some PB Blaster and letting it soak in might make the job easier too. PB is one of the best "liquid wrench" type products out there to loosen seized fasteners.

There are easy out kits. You would need to drill a hole through it and then insert the easy out. It's designed to turn counter clockwise and tighten up in the hole.

Not necessarily the best but it gives you the idea.
Youtube vid: Broken Bolt Removal from Engine Block - YouTube

This article might be of some help too.
http://www.motorcycle.com/how-to/how...rews-3440.html

Carefully heating the area could help it release too.

 

It's not broken - yet, so you still have a good advantage with the head intact.
Impact. Put the bit with extension on the bolt and rap smartly with a hammer, add a handle and turn slightly while rapping smartly with hammer. (A third and fourth hand may be helpful) A dead blow hammer is NOT useful in this case.
If unsuccessful, find the closest, (larger) allen bit to fill the hole and proceed as before.
The trick is turning slightly while smacking hardly, and at the same time to avoid camming the bit out of the hole.
Next option, cutting a slot in the top and using a large flat blade screwdriver proceeding in a similar manner.
Lastly, remove the one screw and cut/drill the head off the contrary screw, remove the housing and remove the remainder of the screw with vise-grips.
I've a hand impact driver and a cheap air butterfly impact that work well in these cases.
Ed

 

that bolt, always strips.

 

It does if you come at it at an angle. You have to hit it straight on with the right torx. Most socket style torx have too large of a head that rubs on the surrounding area causing it to not be aligned correctly. Gotta hit it straight and you'll get it. But, now that its jacked up, if it were me, I would drill the head off, take the other bolt out then use visegrips to take the other stud out, most likely when top of the water jacket is off you will probably be able to take it out by hand.

 

I agree with BoxPin. I used a speed handle to take it off and had no problem.

Thermostat replacement instruction on a 1995 Volvo 850 T-5

 

yep, when i stripped mine it was probably because i used a regular torx bit and because of the head, its impossible to hit it head on due to the socket thickness.

what you need is a long torx so there is no interference.

 

Thanx guys for the good ideas! I'll give Ed's idea a try next weekend. I did soak both bolts with PB Blaster and let it sit for about an hour while I changed the oil and trans fluid.I noticed it was stripped as soon as I put the Torq bit in there. I tried turning a little bit but, didn't want to strip it any more. I'll report back once I try this.

 

I second the idea of hammering a socket on there. A similar idea worked on getting one of those special lug nuts off when I lost the key for it.

And knock on wood, but I just removed my t-stat bolts to replace a stuck open t-stat. I had no issue when using a T40 connected to a 1/4" impact driver with about a 6" extension.

 

Removal video if stripped:

 

I almost never strip them. I use the bit shown with a speed handle. My guess is that I'm almost dead on straight, with 5 degrees. One of my buddies has an allen style torque bit set that has a long shank, use that with a crescent wrench on the top end and it comes right out.

I don't have the tools to cut a slot on top of them.