Can someone try and offer me an explanation for the reason this keeps happening? I have replaced the thermostat housing/ gasket twice now, and will be doing so again today or tomorrow. It seems to leak from the same spot each time... Around the top bolt. I use thread sealant but maybe I am using the wrong stuff (regular blue sealant from the store)? Can the bolt just be worn out? I know it isn't stripped because I am always careful reinstalling it and the threads always grab. I am at a loss and highly annoyed. Thanks y'all! Merry Christmas, happy holidays, and God bless!

 

I wonder if the housing is warped. If so, either "resurface" it with a large belt sander, or replace it.

 

HERE IS WHAT I WOULD DO:
1)make sure both surfaces are very clean before you install gasket.
Use a razor to get all the crap off.
2)make sure the housing its self is not cracked or dented.
3)try another gasket from a different store.(not all are created the same)
4)try liquid gasket.
5)if you have to buy a new bolt
6)if that still dont work tap new threads CAREFULLY and stick a new bolt in there.
i really think once you get to number four you will have a solution that works for you
good luck

 

I have used blue rtv on the gasket and replaced the housing. Gonna replace it again today for the hell of it. Also I don't think I need to tap anything because the bolts are always hands threaded, turning counter clockwise first until the threads click, then tightening. They tighten no problem every time. Always scrape the mating surfaces clean as well.

Edit: it isn't right after the install that this leak happens. The past two times it has been later on randomly like a month or so later.

 

Clean it, stick a gasket on it, ultra black rtv, bolts snug.

Never leak again.

 

The blue may not be high temp resistant, your coolant may be corroding it. ULTRA black is good for just about everything

 

the only think i can think of is to retorque after it has been running hot to cold. if it a reoccurring problem i would check the torque specs for those and crank on them every 100 miles or so.

Another thought when you do the install you should bolt those suckers in while moving around the housing. there are three bolts there right? i think they are 10s? well it dont matter now.
start at the one that leaks crank till it starts to stiffen move to the next one do the same for the last one. progressively work your way around until all are a torque spec.

 

I'll work with it again and give that a go. Wish it luck. This job is getting annoying lol

 

lemme know how it goes. i just jumped in my xj tuned the key and nothing... so your better off than me right now.

 

hm... make sure the blue is high temp and the bolts also could be loosening,,,

 

By reading some of these posts, can black rtv (the stuff used for our diffs) be used for the tstat and housing?

 

Dont even need sealent if gaskets being used ,are you sure bolts tightening down on housing ? Other word if i recall holes dont go thru they stop if bolts hitting a little in the bottom it cannot tighten housing down adding a flat washer will cure it if this is the issue.

 

Reckon using new hardware and some washers would hurt anything? Just to ensure it is tightening?

 

This rings a bell... there was a thread a couple of weeks ago where inside the block the boss for that bolt rusted away or something like that. cruiser54 recommended using the same sealant/thread locker that gets applied to the (#11? #12?) head bolt. Ultra Black RTV should work too, that stuff is beastly.

 

I remember that thread. It was the lower bolt. Mine seems to be leaking from the top bolt but maybe the same reason?