pineapple_tree

I’m in the process of changing my thermostat, and I ended up replacing the housing as well because of how rusty it was.

Now, for some reason unknown to me, it won’t stop leaking. I’ve made sure the bolts are in the right place, the gasket is installed right, each bolts are torqued down to spec, and i’ve even tried two separate gaskets and housings, and it STILL leaks, even if you only fill it up cold.

Now, am I supposed to use some RTV and slather it on there? Or am I doing something else wrong?

Im really in need of some help because what was supposed to be a quick swap in and out, has turned into 5 different runs to the parts store

emx72

We had to use the gasket + rtv for it not to leak

DustyWagoneer

Yeap!
Remember that if they are aluminum, and if they are old you get a little warpage, and corrosion on them. If they are steel............. well it still is gonna get corrosion on them (rust, and pitting).
So yeah use a little RTV.
One thing I do is put a light film on both sides of the gasket, then just get the bolts in there. Let the RTV set up for a few, then torque down after an hour or two.

An old AMC engineer that goes by sc397 on the AMC forum, and IFSJA forum taught me that.

dzywicki

Make sure the thermostat is staying in place as you put the housing on. I have been caught by this a few times where I put the thermostat in the groove and then put the housing on. Everything seems to be in place, but the thermostat slides down out of the indent and is not seated. I use a very small dab of RTV to hold the thermostat in place and it has solved my problem.

Ralph77

Cleaning up everything is key IMO.
Including the channel the thermostat sits in.
To keep it from slipping out when putting it back together.
When I did the water pump and thermostat housing in my '00 I did it dry.
Used FelPro gaskets instead of the supplied paper ones.
It was awkward but doable.
I am assuming you did use thread sealant for the temp sensor in the thermostat housing.
There is one thing that I am wondering about.
All the bolt holes in my '00, for both the water pump and thermostat housing, were blind holes.
No thread sealant was needed on any of them.
Why do I think that is not the case for all Jeeps? That some bolts do require thread sealant cause the holes are not blind.
Even if I am correct in thinking this can't remember if it was the water pump, thermostat housing, or both.

Philippe L.

It's also important to notice that you need to tighten at the same time. If get one tightly and the other one after that, it won't sit right.
This was the mistake I made my first time.

Winterhawk

I noticed you replaced the housing as well. I'm assuming the new one is Aluminum and I would check the mating surface with a straight edge to make sure it's level. I just replaced my thermostat and after cleaning both surfaces I used a Felpro gasket which is peal and stick. I only put a very thin layer of sealant on the opposite side and a dab of sealant on the thermostat to prevent it from moving and then torqued down the bolts evenly. Like it was mentioned, it's easy for the thermostat to slip slightly and the housing won't seal properly. I know it can be frustrating but back up and check the surfaces and make sure the thermostat is seated and you shouldn't have a leak.

pineapple_tree

I think what i’m doing wrong is that the thermostat is slipping down some before I tighten it. I bought some thermostat RTV and when I get home, i’ll use that to hold the thermostat in the head, use a little on the sides to hold the gasket, let it sit for a while, and then tighten them down evenly.

And maybe this time it won’t trickle down and waste more coolant

Dawson89xj

That can be a common problem you can always block sand//poormans mill the housing if its warped and go from there.

pineapple_tree

Turns out all I needed was to tighten the bottom bolt more than I thought I should. The RTV worked like magic, and I used a Fel-Pro gasket instead of that crappy paper gasket, and it still leaked.

However, I don’t fully understand what happened here, but when it was leaking, I went to tighten the bottom bolt and the whole housing shifted, and allowed me to tighten the bolt all the way, and no more leaks!

I still think it’s dribbling coolant at a very slow rate, but at this point, i’m glad it’s not pouring out like it was. If it really is still leaking, then i’ll make sure to fix it, but for the time being, it looks like it’s only leaking a minuscule amount

Thanks for all the tips y’all!