Stripped bolt head on Thermostat housing

Afternoon!

As the topic says, I've stripped the bolt head on one of the Thermostat housing bolts. The other managed to come out (turning t slowly), but I now have about 1cm of a threaded neck without the head on.

I've WD40'd the area, I have also sawn a slit into it to get a slot screwdriver on it, but I was using a rachet set to get it off and I don't think a screwdriver will provide enough leverage/torque.

I've also tried to file either side of the thread, get molar grips around it but this also hasn't really done anything.

Any suggestions?
I was thinking of migwelding a nut onto it, which I can then use as a bolt head and get a rachet socket on it and try and unscrew it. Obviously migwelding has to be carefully done due to aluminium manifold..

Any help most appreciated!
Andy
 
Richard Moss said:
Grind the head off and lift the stat housing clear - then get the grips on to it.

As I understand it the head of the bolt has snapped off, the stat housing has been removed already, leaving what amounts to a stud sticking out which he's already had a go at with Moles.
 
harveyp6 said:
Richard Moss said:
Grind the head off and lift the stat housing clear - then get the grips on to it.

As I understand it the head of the bolt has snapped off, the stat housing has been removed already, leaving what amounts to a stud sticking out which he's already had a go at with Moles.


Yes the housing is off, about 1cm of thread sticking out with the bolt head sheared off.
I might have to resort to the mig welding, and just be careful not to over cook anything close by!!!
 
Maybe just heating it with a blow torch and using mole grips will be enough to free it. Other than that I would go for Harvey's nut welding trick.

Seems to be a bit of a common problem. Along with a few other forum members, I managed to shear one of mine when I was replacing a knack'd thermostat. At the time I didn't have a MIG welder and didn't know about the nut welding trick. I ended up drilling it out and tapping the hole in the housing to accept a slightly oversize bolt. This wasn't pleasant. I haven't had an opportunity to try welding a nut onto sheared bolt yet. Given time and an old car, I'm sure it's only a matter of time :LOL: .
 
get a hammer and a stilson wrench. few whacks to the bolt then a sharp pulled with the stilsons might work I have had good results like this where mole grips have failed. Other wise drill it out.

Colin
 
Like Harvey said, MIG a nut onto the stub and it will come out once it cools.
Welding shrinks when it cools and this frees the thread.
 
After 6 attempts and 6 nuts which didn't bring the damn sheared bolt out, it finally came undone.
Now I can reassemble!
Cheers for advice gents
Andy
 
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