CommanderXJ

Been dealing with this whole issue now for awhile. I replaced the thermostat twice before, and got an all new housing along with new gaskets for both the thermostat and the housing.

For some reason, it still seeps out coolant. I've noticed within the last month or so that my coolant has been draining faster than usual and I finally figured out why. Doesn't happen when the car is up and running, but if it sits for awhile I can see coolant seeping from around the thermostat housing area.

Any idea what could be causing this? The screws and everything are all torqued to factory specs so I am at a loss.

OverlandZJ

Was the replacement thermo housing new?

I have a bud who kept having this issue. I tore it down and noticed the thermostat had fallen out of it's recess in the block causing the leak. Some good silicone (just a tad) on the outter diameter of the thermostat helps hold it in position as your bolting on the housing. I like "The right Stuff" for jobs like this..

CommanderXJ

Yep, brand new thermostat housing. I just used the regular paper gaskets. When it didn't seal properly the first time, I went ahead and bought two thermostat gaskets and put those in addition to the thermostat housing gasket.

I thought it worked but apparently not

RLR

if you use more than one gasket at a time you have a better chance of it leaking. unless i just miss-understood you comment. but anyways mine did the same and i just put a little scilicone on the housing and now it good. ........ but why were talking about the cooling system, mine jeep is overheating and loosing water everyday. i jusr put in a new radiator and water pump. when i turn the jeep off i can hear it boiling and then it starts dripping.... definately not headgaset. and i didnt look to see where it dripping but i will in the morning. but anyways why is it still overheating??

CommanderXJ

Hm, the boiling problem could be the radiator cap. I remember when I had my old Camaro it used to boil after I drove it. Once I got a new radiator cap however the noise went away.

Maybe someone else can chime in with the overheating issue.

davida

I understand the thermostat housing gasket but I don't get the thermostat gasket? I just replace my thermostat and only used one gasket and that was for the Housing. Mine was a 96 4.0

rich

the way he talks hes got 3 gaskets on it, you only need 1.

Hommersimpson

take housing off... make sure the state was centered in housing and not sliped on the lip it supose to be in... get some 180 grit or so..and lay on kitchen couter ( flat surface ) and sand bottom of housing.. look at it.. is it flat ? you can tell with just a few strokes on the sand paper if its flat or not.... clean head good... check and look for crack around bolt holes..

alaska xj

Make sure both surfaces are clean and DRY. I used some shop towels to saok up some of the coolant that likes to seep out near the bottom of the thermostat opening. After getting a bad thermostat I had to replace it and got one at Napa, one at Shucks and the Gasket that I got from Shucks was way better. Napa had paper cut out and shucks had and actual gasket. I used a dab of RTV around on both sides and waited like 20-30 minutes before filling with coolant to make sure the RTV cured a bit. Haven't had anymore probs. Hope this helps.

ClutchKimball

I too have had Thermostat gasket sealing woes. The way I fixed it was to CLEAN EVERYTHING. get a scraper and some emory cloth and sand all the rust and old gasket material off of the head, then I did the flat sandpaper on the counter method, as described earlier (by Hommersimpson) with the Housing itself. Then I sat on the bumper to allow as much coolant to come out of the head as would come out. Then I propped a spare tire under my bumper to hold the front of the jeep up, so that the level of the coolant went down even further. I then cleaned both mating surfaces with Brakekleen, cleaned out the bolt holes with a Q-tip to make sure there was no coolant hiding in there, and wiped the surfaces with a clean rag.

Make sure to get the fiber Felpro Gasket. It is a little more expendsive than the paper gasket, but it is a quality piece. I then used Permatex Spray Gasket Sealer on both sides of the Gasket. It is a tacky red coating that helps both seal once torqued down and provides some adhesion during assembly. I used some Thread sealer on the threads of the bolts...Im not sure why, cause they are blind holes, but I wanted to do everything I could to make sure it wouldn't leak again. I tightened the bolts pretty tight too. Been holding fine ever since.


On the overheating/boiling issue....I agree with CommanderXJ on the Radiator cap. The reason for a Pressurized cooling system, is that the higher pressure that water is under, the higher the temp can go before water boils. I don't know the exact Temp/psi ratio, but if water Boils at 212*F and your Jeep likes to run right around 210*F then you need that extra 16 lbs of pressure in your cooling system to keep the boiling point high. If your Radiator cap is not sealing in the freshness anymore, then you need another one. Cheap fix.

trans_am7935

X2 on that one. clean it, scrape it, and use a normal gasket seal with RTV clear silicone. apply to thermistat itself so it sticks to the block, then the the housing slit so it doesnt leak. you should have no problems. just give it an hour to dry after it is all installed to be safe.



the PSI should be around 15 psi. also you should change your fluid, get a gallon of concentrate, and 2 gallons of DISTILLED WATER and fill it up the rest of the way. distilled water is pure and has a boiling point of like 400* or so. it will allow for better cooling and protects the radiator from corrosion. changing the radiator cap couldn't hurt anyway. good luck

RLR

alright thanks ill give it a try.... but how the hell does distilled water have a bp off 400?

ClutchKimball

I want to say I heard that in science class once. Something about not having any impurities...but I really dont think once you put it into your dirty radiator, that it is going to make any difference.