Stripped bolt on thermostat

[JimBee]

I found a picture of the stud I removed with the two nut technique:

[xHeart]

Just drill it off. The torx well will help keep your bit centered. Use some oil on it. Get up over your drill so you can load some weight on it. Keep your drill bit nice and vertical—square on the head. That will give you a nice clean, square threaded stud to work with when the screw head is off.

Before you drill, work a paper towel or rag under the t-stat housing to keep filings out of your alternator, then carefully remove it when your done.

The thermostat housing has upper and lower parts. Is the upper part threaded? I mean, does screw travels on the thread before reaching the lower part, as oppose to slide pass the upper part, and then catches, and continue threading on lower till tighten.

My concern is drilling a screw which pulls and fastens two surfaces could cause permanent damage to the housing itself.

If the upper part has no thread for screw to travel, then it is a lid, hence easy-out type of method has better chance of success.

The other hesitation is bit size with length that would clear the fuel rail. What size drill bit would come close?

[Ozark Lee]

The thermostat housing has upper and lower parts. Is the upper part threaded? I mean, does screw travels on the thread before reaching the lower part, as oppose to slide pass the upper part, and then catches, and continue threading on lower till tighten.

My concern is drilling a screw which pulls and fastens two surfaces could cause permanent damage to the housing itself.

If the upper part has no thread for screw to travel, then it is a lid, hence easy-out type of method has better chance of success.

The other hesitation is bit size with length that would clear the fuel rail. What size drill bit would come close?

The upper part of the housing is not threaded. You can drill away with no worries.

For drill size I use a drill that is slightly larger than the diameter of the bolt - I can't remember what size off the top of my head - and just pay real close attention to the fuel rail.

...Lee

[xHeart]

The other hesitation is bit size with length that would clear the fuel rail. What size drill bit would come close?

The upper part of the housing is not threaded. You can drill away with no worries.

For drill size I use a drill that is slightly larger than the diameter of the bolt - I can't remember what size off the top of my head - and just pay real close attention to the fuel rail.

...Lee

I picked up 2 housing screws, the thread would take 7mm nut = 0.275". My two bit choices are 9/32 = 0.281", 19/64 = 0.296". These two are close to 7.5mm. Do I need to go closer to 8mm?

I would place a stopper ring on the bit to take off the screw head's only, and not travel beyond 1 - 2mm after the head. Would 21/64 = 0.328" about 8.2mm diameter a better choice.

It brings me a step closer, thanks Ozark!

[xHeart]

There is also a choice of 1/4" left-hand drill bit.

[xHeart]

I found a picture of the stud I removed with the two nut technique:

The attachment T-stat stud w nuts.JPG is no longer available

I am thinking of using the two nuts method. The nut size is 7MM 1.0.
Would you delineate you procedure on more time. I am not sure it would thread from the top, would it?

shank still needs to come out

MVS_0237.jpg (401.78 KiB) Viewed 1632 times

Thanx!

[xHeart]

Out!

Read here...viewtopic.php?f=1&t=50844

[850TurboTurtle]

I cracked my housing using an impact driver to try to remove a stuck bolt on the thermo cover. So yes, use PB blaster and/or heat, and get better bolts before reassembly. I was in Portland when I cracked my housing, and the nice guys at IPD gave me a few new bolts for free. And told me some fun stories about tweaking a turbo 850 for speed... So, overall, not an entirely bad experience.

[850TurboTurtle]

PLEASE DO NOT USE AN IMPACT DRIVER TO LOOSEN THE THERMOSTAT BOLTS. I have already cracked 2 thermostat housings in half in the past 4 months. They can not take the shock of an impact hit. Drill or grind off the top of the bolt, lift the top of the thermo housing off, and remove the remainder of the bolt with vice grips.

But never never never hammer on the top of that aluminum housing unless you plan on a trip to the pull a part.

[rspi]

Here is a video to help some.