NTX JK

I have an 07 with 50k miles on it. It has been leaking at the thermostat since around 25k miles and I have taken it to the dealer twice. Both times all they replaced was the thermostat, and it continued to leak. Now that my warranty is up, I started to look at it a little closer. I replaced the thermostat myself, it still leaked. I added one of those cork gaskets (the kind that comes in a 8.5x11 sheet and you cut to fit (also, JK's dont have gaskets, it is just an o-ring on the thermostat btw)) and it still leaks. I was watching it, and it is coming through the bolt on the driver side of the housing. Is it possible it is leaking from the bottom of the bolt hole and not actually through the coolant passage? I was thinking about putting some kind of thread sealand on it, but I don't know what I should use so it can withstand that kind of heat. Any thoughts?

rich1340

Just use some high heat silicone or even Teflon tape.

ronjenx

When you take it apart to seal the bolts, remove the extra gasket while you're at it.

Hulk

Did u ever find out what was causing that? Mine is doing the exact same thing and I'm at 44k on my 07.

Hulk

Or has anyone else had that problem? It's a little strange unless the housing warped

Will

I smelled burning fluid for several months and noticed that I was slowly losing radiator fluid. I found the small leak around the thermostat housing. I found out the plastic housing had cracked and that was were it was leaking.

trick50

the o-ring goes in the middle of the housing, although there is no gasket you are still supposed to use high heat silicone i usually use RTV around the housing circling the bolt holes, in addition it wouldn't hurt to put teflon tape or pro-dope around the bolts before installing them.

ALs07

Look around theres a gasket expecially made to go under the housing. I put one in my JK ,60K miles. Felpro pt# 35651, $ 4.99,

RDLNJK

Felpro gasket is definitely a good idea, considering there is no gasket. Mine was leaking from thermostat housing. Put a new Mopar thermostat in and Felpro gasket. Pressure tested and no leaks.

RedJeep91

I also was noticing a slow drop of fluid in the radiator reservoir. However, the leak is not coming from the thermostat housing, it's coming from the temperature sensor just behind it on the right. Have not fixed it yet, assume it just needs a little sealant and reinstallation.