Advice on snapped therm housing bolts...

Jeep School

Bigger Hammer
Mar 19, 2010
Willys Model
Willys Year:
Howdy. Okay, everything has been going way too smooth, so had to hit my first speed bump: when we removed the thermostat housing from the block, BOTH bolts snapped off in the block. Soaked with PB. Tried to drill and "easy-out" them out--broke the easy out. My inclination is to drill-baby-drill and so be it if we have to custom tap new bolts. BUT, since we are trying to keep this clean and factory, do any of you have any better ideas?
Best way to drill it out now is use Cobalt drills as will be too hard for a normal drill bit. But you are best to soften the steel bolt and the eazy-out by heating it cherry red with a oxy first. Then let cool down SLOWLY. Do not try to cool it faster as will have the opposite effect. Might be able to use a narmal drill bit now too.
If there is any sticky out, what I do is place a nut over it and fill the nut with weld from a mig. This gets the heating you need saving you using a oxy and allows you to put a spanner on it and screw it out.
Gojeep said:
place a nut over it and fill the nut with weld from a mig. This gets the heating you need saving you using a oxy and allows you to put a spanner on it and screw it out.

This method has worked well for me quite a number of times.
Based upon your description I would just call this a 'loss leader'. The suggestions above are all good but I think if you are snapping the ez out then my bet is you will need to pick another door.

In this case its "drill baby drill'. You would be WISE to obtain the proper drill bits to do this with. Home Depot sells a set of Rigid bits that have been extreme cold treated. They are good but EXTREMELY hard and care must be taken NOT to bend on the bit or it will snap, but straight on drilling its excellent. Sears sells Boron bits which are also good. You can buy them individually thus saving some money. The Rigid bits are about $45 bucks for a good set...BUT the do come with a lifetime warranty. Break, bend or otherwise fail due to what ever and just take them back to HD and they will cheerfully exchange for a complete NEW set (I am on my second set and had zero issues doing an exchange).

Having said that I would 'pray' the Jeep Gods are on your side and you can extract the bolt and save some threads. If not then go for the drill. Your key worry is the holes are not parallel. Its very difficult to accomplish using a hand drill...BUT all is not lost. Not likely that using a hand drill will cause the drill hole to be sideways, but rather the drill 'n tap will end up slightly off. As this is apt to happen then here is a cheap and quick fix:

You will need 2 washers. One should be a flat grade 8 (Ace Hardware). The center opening should be slightly larger than the bolt head. Then a soft washer such as a mild steel or even copper. This will need to be larger than the opening in the grade 8 washer. Now put it together using the grade 8 washer under the softer washer. The softer washer will slightly deform and by having the opening larger it will allow the deformation to be both off center and off-camber in relation to the other bolt. Torque on the thermo bolts is about 35 -40 lbs in most cases and this will allow that.

Let us know how this evolves... ;)
Okay, bolts are out, so to speak. I called in Darryl. We tried everything over the last couple of weeks. I went out every day and gave it a good soaking with PB. We tried heat. We tried drilling with teeny-tiny bits around the easy-out, etc. Basically, a little of everything helped on the one bolt, but on the other one that broke the EZ-out Darryl still had to resort to a BFH, and tap and die to "rebuild" the threads. He did a beautiful job. It was a good exercise in patience for both of us.

Now I am a happy camper because in the meantime, I was able to go through the rest of the fuel and cooling systems, order any necessary parts, clean everything up, and am now in the "putting everything back together" mode on those systems.

Thank you all for your input! May the Willys gods smile on your bolt removal!