Stripped bolt hole for thermostat

[Evan Wood]

Stripped bottom hole to thermostat housing, should I helicoil it or tap and die? Plus should I have some one do it?

 

[cobrajeff96]

Most likely you'll have to helicoil it. It's super easy to do. Youtube it if you have to. You can find a helicoil kit just about anywhere, especially online.

Another option is to just through-bolt it with a nut on the other side of the flange, that's probably the quick/easy but janky way to do it.

 

[Evan Wood]

Thank you.

 

[whiplash473]

another option would be to go with the next size larger SAE and tap new threads. I should remember as it was just a week ago that I had mine off but it’s either an M6 or M8 in there from the factory. If it’s an M6 you could grab a 1/4-20 screw and just hold it up to the hole and see if you think that would be enough to work. If it’s an M8 you’ll probably have to go up to a 3/8-16. But that really doesn’t seem right - too big. So give the 1/4-20 a shot.

Just be careful to call it quits when you feel it bottom out. With it being aluminum this should be easy enough to tell.

 

[whiplash473]

without looking at it in person I’m not sure if there is enough space on that boss on the inside of the flange for a 5/16-18 but that might be a better option. The first picture of a M6 in a 1/4-20 hole. This is actually one full turn into the hole. Might be a little too close for comfort if you’re going for the 22ft/lb torque on the thermostat bolts. So close that you’d essentially be tapping a crossthread. I’d give it a shot in steel but I don’t think I’d chance it in aluminum.

The second picture is a 5/16-18 next to the same 1/4-20 hole. I’d probably go this route. Again, if there is enough meat surrounding those threads to accept it.