Changing thermostat - broken bolt

[n0c7]

93 Explorer XLT, about 4 years ago I replaced the thermostat when I bought the Explorer. While reinstalling the thermostat housing, the head of one of the old rusted bolts snapped off. The thermostat housing never leaked and was tight so I left it(no use making more work) as I didn't plan to keep the vehicle that long. Turns out, 4 years later it's still here and the thermostat is most likely toast as I had a overheating issue this summer. Any suggestions on getting the snapped bolt out? It's in a really bad spot as most of you who have done thermostat swaps in X's would know and to drill it out and it looks like I would have to remove the grille and rad at the very least just to get enough clearance and leverage. Yay for vertically mounted thermostats.

 

[leefhead]

if there is still part of the bolt showing, theres this lovly tool
http://www.sears.ca/gp/product/B000..._33?ie=UTF8&searsBrand=core&mqnodeid=16361911

 

[n0c7]

Nope, unfortunately there is no head. It's clean off right at the hole. I have a set of those somewhere too. Dang.

 

[leefhead]

that sucks....could try using one of those screw outs (same type of thing, but for screws), just take er ez....use a screw driver. couldnt really thing of any other way...maybe a reverse direction bolt....drill in it a bit with a small drill bit, torque down the reverse direction bolt, and essentially it should be unscrewing the other bolt...you could mail me those bolt outs though

 

[DeRocha]

Nope, unfortunately there is no head. It's clean off right at the hole. I have a set of those somewhere too. Dang.

Is it even with the block or the thermostat housing? If its the housing you should be able to lift the housing over the bolt and just use vice grips to remove it.

 

[n0c7]

Is it even with the block or the thermostat housing? If its the housing you should be able to lift the housing over the bolt and just use vice grips to remove it.

It's even with the housing I believe. So what you're saying is, remove the other two bolts and basically spin the housing around until its off, and vice grip out the remaining bolt? That might work if there is enough clearance for the housing to spin 360.

 

[DeRocha]

It's even with the housing I believe. So what you're saying is, remove the other two bolts and basically spin the housing around until its off, and vice grip out the remaining bolt? That might work if there is enough clearance for the housing to spin 360.

Kind of... The bolt holes in the thermostat housing aren't threaded so the housing should just pull off when you remove the other bolts..

 

[n0c7]

Kind of... The bolt holes in the thermostat housing aren't threaded so the housing should just pull off when you remove the other bolts..

Oh really! That shouldn't be too bad then. I was under the impression that they're threaded, but its been almost 4 years. Good call, I'll give it a try when it warms up a bit.

 

[knob]

I did the same thing and ended up replacing the lower intake manifold. Probably the best fix for this and the new manifold cost me $60 from a junkyard.

 

[n0c7]

So I got around to doing it, the housing came off just like DeRocha said. Unfortunately, the bolt is actually snapped off clean in the block so once again I could not remove it without taking half the front end apart. The thermostat "pin" totally popped off from the center, so it was definitely shot. Slapped on some RTV fairly thick, locktited the two remaining bolts, and put it back together. I forgot how much of a pain in the ass it is, managed to remove without taking the belt off, but still had to take it off to reinstall the housing. Also took the time to clean off the sending unit contacts as the temp gauge never worked even after replacing the sending unit. Added a dab of vaseline in there.


Result - lots of heat, and the temp gauge for once in 4 years works. Just crossing my fingers that it won't leak, but if it didn't in 4 years missing one bolt, why would it now?

 

[DeRocha]

Glad to hear your thermostat has been replaced and your heat is once again working. As you have already surmised if the thermostat housing held for several years with a broken bolt then the sealant and the remaining bolts are enough to keep it leak free..