Tapping Threads for Thermostat Housing Bolts

[kdenmcfish]

Hi All,

My shit box has been dumping coolant for the last couple of weeks, which I have officially diagnosed as a loose thermostat housing, at least so far. Turns out 1/3 mounting bolts going into the head is completely stripped out.

I'll be pulling my radiator in the next couple of weeks so I can fit my drill into the bay and install a Duratech Thread Repair (Helicoil) insert, but was really hoping somebody with more knowledge than me could get my plan as I have never attempting this before, let alone in my head.

Took the bolt to Ace, M6 x 1.00 x 20, picked up three new bolts and washers (if needed), figured I might as well do all three as the kit permits. The kit calls for 1/4" bit (6.3 mm, the DeWalt drill bit I have is 1/4" 6.4mm, beats me, I'm assuming it'll be fine?).

Anything specific I should be thinking about here, any tips? What is the appropriate torque spec with the Helicoils? TYIA.

 

[Curious Hound]

1/4" is actually 6.35mm. So, your drill bit will be fine.

 

[pentode]

Helicoils/thread inserts don't require any real amount of torque - each different brand usually has a pretty specific procedure to follow. Mainly it's about drilling/tapping to the right depth and installing the insert until it's flush. Some types have a tool that you use to swage the insert into place - I don't know about Duratech. There's a debate about using thread locker on the insert. Usually they recommend you install them dry but I've done it both ways and never had a problem. Really shouldn't make a difference.