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Thermostat housing bolts broke off 4.3 sonoma

Your drill should have enough torque to drill a hole. A left hand drill bit will unscrew a bolt if is somewhat “free”, a corroded, seized bolt won’t unscrew that easy.

If the bolts are badly seized you will need to drill them out completely but only up to the treads. A screw extractor will only cause the bolt to expand making the problem worse.

I hope it does . I’ve had them soaking in Blaster PB all day.

So if it doesnt come out and I have to drill the bolt out how do I fix the threading?

I use a drill bit that is smaller than the threads, then peel the threads out with a pick. The bolts need to be drilled dead-center.

If the threads become damaged you could install heli-coil inserts but that means a trip to the auto supply store for the kit. If there is enough material in the manifold, the holes could be threaded to the next larger size bolt.

I’m glad you brought u the helicoid insert. I’m not so nervous about doing this in the morning. Thank you

For a hole that small, you don’t need much torque.

I once salvaged an old junk intake with the thermostat threads stripped by cleaning up what was left of the threads and inserting a bolts into the thermostat hole and threading them upward with nuts on the top. That was long ago when I was much more dexterous. These days I would probably use a thread insert.

That depends on how bad the threads are messed up. A thread chaser might help if the threads are not too much damaged. Otherwise you have to tap a new thread. That’s not too hard to do. Lots of videos on youtube.