So I've changed out my WP and now on to my T- stat, problem is original owner broke the bottom bolt off in on the head but instead of tapping the remainder of the bolt, which I'm assuming couldn't be done? (Take a look at the pic) he just drilled a new hole through the T-stat housing and into the cast iron head.
Looks like I'm going to have to go with there fix.
What I'd like to do if possible tap out that bolt -
And run a new bolt in not very tight but just for a little better seal. ?
What I you guys think dangerous ?

 

Looks like that ' bigger' hole (I take it that's the fabbed one) is missing part of the side.
I'd give it a try to get that broken off bolt out of there no matter what and use the original location for the bolt.

 

No the bigger one is where the main bolt goes.
I just wonder if I can hone that out without cracking the head. My plan would be once I get it out, get a couple bites with a new bolt just enough to get slight pressure along w/ the other bottom blot creating a tight enough seal preventing a leak.?

 

Knowing the length of the stock bolt might give you a better idea if how far back into the head it goes. Not being able to see up under that edge...where the water pump is now is a bit frustrating! 3.14 X 1.25 squared x 16 divided by 2 is 39.25. So about 40 Llbs is all each bolt it holding with a 16# cap.

Btw, you should know, my T-stat housing was a weekend job. First the T-stat was "fused" onto the upper bolt. The whole works would turn, not all the way around though. Then later I dropped that washer into my timing belt pulley. Stranded up here I had to have a friend bring me another belt. 1/2 job. Right!

 

That sucks bad sorry to hear that .
At least I'm parked in my drive way I feel Lucky after hearing your story.

 

Will I have to pull my radiator to tap that bolt out?
Any tip on getting it out ?

 

Will I have to pull my radiator to tap that bolt out?
Any tip on getting it out ?
I'll try for a better pic.

 

I had the same thing happen with the head on my 1987 renix. my head broke off worse. I still had a few threads left to snug the bolt up. Just use the right gasket maker and give it time to dry. Give it over night before you fill her back up. You can use water first and make sure it holds up to the pressure. If there is no leaks, drain and fill with coolant.

 

I looked at the picture again, is that a four cylinder motor.

 

No it's a 4.0 L aw4 242tc Dana 35

 

Was it leaking before you removed it? If not, use a new gasket with indian shellac. I doubt it will leak.

 

I constantly check my fluids anyway I would never see a leak coming from the T- stat wish I could've taken a pic . There was always a very small leak right on top of the WP I can actually get a bite on the lower bolt looks like just the tip is in there (see pic ) Maybe to sketchy to tap out/hone out? I wonder how many times this has happen that cast iron ain't no joke
Sorry guys this is a (1990 jeep cherokee I6 AW4 242TC. Dana35s. 3" RC. lift

 

You should find a real computer and fill out your info. It sucks to not not know what you have. This message is to EVERY poster.

My 2686 head does not seem to have that "ear' that is broken on yours. (Heads are here> http://www.jeep4.0performance.4mg.com/tech_specs.html

To your question YES, normally there is a way to extract a broken bolt, and yes, lot's of room is preferable. It's a very tricky business of getting a drill bit started, dead center and lined up. Even a small one. (maybe 1/8 here). That's the "pilot" hole. If that's 5/16 (around 8mm) , I might go out to around 3/16 or 7/32 for the hole for the extractor. Hey, if all goes way wrong, you still have the other deal that worked before. (by "way wrong" I mean you broke the extractor in the hole, and you aint drilling that sucker out!)

Slow and methodical, tranny fluid lube, no over heat the bit. Doable.

You might find that that that the broken part of the bolt is not even tight! Sometimes a dremmel slot and a flat blade screwdriver will work.

In your shoes I'd probably blast the pitted metal with quick start, (ether), let it evaporate, use the brush on the Permetex #3 to get it into the porous surface, then, with the gasket, put it together with the existing bolt hole. Leave it 1/2 tight over night, then snug it in the AM. Yea, it's off center, but it's not holding anything but...well about 4O Lbs of pressure. The tensile strength of a 1/4 inch bolt is more likely closer to a ton. (2000 lbs)

5-90 could sure be of help here....

Looken again at your pic....I'm not sure that isn't the end of a broken easy out. Look good, has it been drilled? Is there something in there? If there IS, bring it by and I'll blast that out with a cutting torch.

 

I really hate to see "Half A**ed S*it" like that on any car instead of doing something right. I guess I'm different than most if it were mine I would replace the head but I understand not doing so because of cost factor. I have always been that way on any car I ever have bought used I want it done right and with good quality parts. I hate doing anything twice costs to much and I'm to cheap.

Hope your repair comes out fine and no future problems with it haunt you.

 

You could drill the stock bolt out as straight as you can and helicoil it. A touch of center (cuz its so hard to get the extract center) would be correctable with the bolt. The trick is finding out the original length of the bolt and going no deeper than that