Uh Oh... snapped thermostat housing bolts.

[fried1765]

Left hand drill bits are great.

Before drilling you need to centerpunch the bolt. Especially since it probably did not break off nice and level. Since it's uneven, it'll need to be larger and deeper than a centerpunch on a flat surface. A carbide bit in a dremel tool works well.

DITTO!
I have two complete sets of left hand drill bits!

 

[fried1765]

Helicoil come with a drill bit to drill the threads oversized. My experience is if a bolt is broken off, not from stuck threads an easy out, left hand drill bits etc will get it out. If it痴 because it痴 stuck and rusted in place, time to start drilling.

Easy outs can be REALLY nasty to deal with, when they snap off, as they often do!

 

[4570Man]

Easy outs can be REALLY nasty to deal with, when they snap off, as they often do!

I’ve had a lot better luck with the drive in wedge shaped easy outs. The spiral ones seem to expand the drilled bolt.

 

[WanaBFarmer]

If there is enough of the bolt shank sticking up I've had good luck welding nuts on.
Open up the hole (taper it bigger up) in the nut to give good access for welding. (Mig is easiest).

This does two things.
heats the bolt up and helps break the oxide bond in the threads.
gives you purchase to work the remaining portion of the bolt.

 

[3930dave]

Van access is often "fun".

I've seen my buddy tack weld nuts on many broken studs, doing exhaust manifolds on PITA engines.... but he's got welding mojo I never will... once the nut it securely tacked on, he'd often gently use an air hammer, with a rounded nub on the end to tap the nut to dislodge rust. Based on science, but takes some art too.....

I think you said heat is out..... back to that van access-thing again maybe....... If I was out of options, I might play around with induction heating, homebrew or otherwise

Mini-Ductor Induction Heater Tool for Repair | Induction Innovations

Can't picture the top of that engine well..... if the gooseneck mating-flange is flush with the manifold, then you may be stuck pulling the Intake.

If it is a stepped-flange, and other options don't work, try a dremel tool and a good burr...... takes time, and not pretty, but beats the scrap heap.

Rgds, D.

 

[true temper]

The bolts broke off because they are stuck in the aluminum thermostat housing. They get corroded to the aluminum and weld them self together. They are not stuck in the manifold get the aluminum housing off and the bolts will screw out easily. Worst case sacrifice the housing. Seen it many times.

 

[ultrarunner]

Plan to use the housing as a drill guide after soaking this week

 

[radios1]

post a picture of this. once you get the housing off, you should get like 3/8" of bolt sticking out of the manifold, weld a nut on each one, and use an impact wrench on low air pressure for a couple of minutes, increasing the pressure after that each time, the vibration should loosen them up!..

 

[3930dave]

With the amount of people I hear talking about running out of things to watch on TV.....

..... do a Live Stream ur, charge 10cents "admission"......... you'll probably have plenty of money for performance parts !

Best of luck..... with your skill sets, you shouldn't need much :thumbsup:

Rgds, D.