Broken Block at Thermostat Housing

I have a 88 Limited with the 4.0 I6. In trying to replace the thermostat both bolts broke. I got the upper bolt however, in attempting to remove the lower bolt with an ez-out, the actuall block where the tapped hole was broke away. Has anyone had this problem or offer any suggestions on what to do?

Thanks in advace for any help.

Can you post a picture? I know what that area looks like in good condition, but I'd like to see what your break looks like before I try any suggestions (I'm trying to picture how it would break through, and I'm drawing a blank...)

5-90

That happened to me. The lower part of the threading broke off, leaving it impossible to put the t-stat housing back on.( not enough threading to catch the bolt) I had to get the hole tapped out and installed a larger bolt. Now it just has a little extra RTV on the gasket.

Easy outs should either be made illegal or renamed to 'The Fu*k it up worse tool'.
I'd rather drill out a broken bolt and rethread or helicoil than allow an easy out on my property....

C'mon, easy outs are great, you break a bolt off, drill a small hole through the broken bolt, insert the easy off (which is hardened steel, stay tuned for Irony), you then start to twist on the easy out and.....Snap....No thats not the sound of the bolt coming loose, rather its the hardened steel easy out that has snapped off clean with the bolt that has yet to move (insert Irony here) you now have HARDENED steel in the center of the bolt which is now going to keep your drill bit from lasiting more than a couple revolutions! You can now proceed in cussing and swearing and might just as well break out the Oxy/acetalyne torch and finish her off.......


Anywho, about the prob at hand. If it comes down to it and you are unable to drill larger and thread it to make things kosher, you could have a small tab welded to the thermostat housing and relocate teh bolt slightly so you can start a new hole and rethread.

I somehow got the wrong bolt (a little to long) wouldn´t seat, in a hurry and tried to muscle brain it in there. Broke off a piece of the block.
I used a counter sink to widen the top of the hole, installed a stud and spot welded, in a few places. The excess material, I removed with an air grinder (dremel). I unpluged the CPU, TCU and every module I could think of, before welding (just in case). Studs been in there for 6 or 7 years. been through a couple of thermostat changes.
Welding cast iron can be an iffy thing, I got lucky and nothing cracked or spalded.
The only time I use an easy out, is when the bolt isn´t frozen. If I can see any kind of movement, I´ll try an easy out. If it´s frozen, I drill through the center (gotten pretty good at it) using bigger bits, until I just skin the threads. Use a sharp punch to bend whats left of the bolt towards the middle (in a few places) and work it out of there, with needle nose pliers and/or a screw driver. After the intial hole drilled through the center, I often use a battery drill, slower speed, torque adjustable, so as not to break off a drill. Requires a touch, but works well.

The trick to welding cast iron is heat - have a helper bring it up to about blue or so with a torch before you hit the arc. I've assisted on some block welds, and that was always the trick. Since cast isn't usually tempered, that won't be an issue.

5-90