Topic: Coolant system replace help

[cyberdyke]

Hi,

I am in the process of replacing my coolant system (radiator, hoses, heater hoses, water pump, thermostat).  I have run into a problem that I would love some feed back on. Refer to the picture here: http://tinypic.com/r/123rrqd/7

After getting a good portion of the rig back together I remembered that I had forgotten the thermostat.  I removed the Therm housing and the therm, cleaned off the therm housing with a sharp paint scrapper as well as the section of the engine block that holds the thermometer, removing the used gasket.  See Pix #2 and #5 for condition after being scraped.

Since my therm was stock I immediately ran into the problem that it no longer matched the new thermostat see pix #1.  You will see that at the top of the old therm (on the right hand side) there is a "hole" and an arrow with "UP" next to it.  My parts store, that I have used for years and trust, assured me that these new "aftermarket"' thermostat don't have the "hole" and the "UP" - but it doesn't make any difference the thermostat will function the same.  I installed the thermostat as it looks (left hand side) of pix one. And then put the gasket over it, as it shows in the FSM page 7-24: http://www.scribd.com/doc/27977648/1999-Jeep-TJ-Wrangler-Service-Manual-07-Cooling-System.  Tightened the bolts according to the FSM to 15lbs.  Connected the hoses, tightened up the drive/serpentine belt, and began to pour coolant into the system.

After about 1.5 gallons of coolant I noticed a puddle under the car. After throwing a drip catching container under the leak I began to search the engine to track down the source of the leak.  I find it dripping out of the bottom of the thermostat housing.  See pix #4 (at the bottom of the pix you will see the red on the left side of the pix.) The leak was to the right of the "red" right above the exposed bolt that is in a direct line to the red at the bottom of the pix.

I drained the coolant out, checked the bolts with 2 torque wrenches and everything checked out. To verify that it was still leaking I put in about a gallon of water and she was still leaking.  I drained the water, removed the housing, cleaned off the gasket, inspected it for cracks, holding it up to the sun as well as just looking it over.  After purchasing another gasket and talking to a couple of buds I also purchased some silicone (see pix #5).  I put a very thin bead of the silicone on the new gasket and fit it carefully into the thermostat and put the whole thing back into the engine block.  Once again tightening the bolts to 15lbs.

Once again putting in about a gallon of water (why water?  Because its not a messy or corrosive if there are leaks) I had the same farking leak!!

What the h*ll am I doing wrong?
Do you have to let the silicone dry first?

Help me Obiwan!

[Jeffy]

Pics aren't working.  What kind of silicone did you buy?  Permetex Ultra Blue is what I normally use since it works on diffs.  Light skin on the gasket.  You're not creating a gasket but helping the paper gasket to seal.  Usually takes a few minutes for the silicone to tack up.

[sharpxmen]

pics are working for me, took a while to come up though. permatex blue it's fine, i used it on waterpumps before with no issues, any silicone works if you're using a gasket as well, i even used the household ones and never had a leak.

@cyberdyke
you're not doing anything wrong, have you considered that the leak might be from somewhere else? you said it only started leaking after 1.5gallons, did you drain it before taking the thermostat out? if you didn't then it leaks from somewhere else (othewise you'd have water to the bottom edge of the thermostat housing. you can add water without the thermostat housing on just enough not to get over the edge and see if it's leaking from somewhere else.

the waterpump looks new, was that replaced as well?

[Nicks92jeeper]

I did a flush once on a Mercury Sable and what happened is the thermostat moved and it was in between the housing created a gap so it wouldn't seal properly. Check that out to make sure it didn't move because when I did that to my Jeep I had the same thing happen but I caught it before I finished.

[Nicks92jeeper]

I wanted to clear up my last comment because I was in a sleep deprived stupor I guess. Make sure that the thermostat is not stuck between the housing and the block. If the thermostat is not in its proper place it will leak like crazy.

[VA_YJ]

Make sure you remove all the old gasket material and sealer.  Use a light film of sealer on both sides of the gasket and make sure the thermostat is fully seated.

I am fortunate enough to have a cooling system pressure tester (from Sears).  It's very useful for finding "mystery leaks".

[Nicks92jeeper]

From the very first link of pictures that I did see, that thing is still pretty gnarly looking. Definitely do some scraping if it still looks like that and clean up as much as possibly like VA_YJ said.

[grumpygy]

I wanted to clear up my last comment because I was in a sleep deprived stupor I guess. Make sure that the thermostat is not stuck between the housing and the block. If the thermostat is not in its proper place it will leak like crazy.

Which means pull it apart you will see the Thermostat is crushed on on edge if it is.  But that would be my thought it came out of the groove.

[sharpxmen]

she installed it twice, once with only the gasket, second time with a new gasket and RTV

[grumpygy]

Has anybody been given the wrong thermostat, cause I have and had about the same problem she is having.  But its been too many years since that happened to remember what was the reason I found it.


Also Pic #3 is that after being installed once.  cause the stain on the right side kind of looks like it did slip out of the groove.

 

[Jeffy]

Well the link still isn't working for me.  Any chance it leaking from the bolts?  I can't remember if the top bolt goes into a jacket or not.

[JohnnyO]

Clean both surfaces real good and use some sandpaper.  Make sure the thermostat is seated well in the lip of the manifold.  The side with the spring goes into the manifold or block.  I use black Permatex on both sides of the gasket and a little bit on the bolt threads.  Tighten everything up and if possible let it sit overnight to cure before you refill it.

[Nicks92jeeper]

From the picture that she had it looked like the right thermostat. I think it just fell down a bit and was wedged between the housing and block. When I did the thermostat, it did not have any jackets for the bolts. Keep us up dated cyberdyke so we know what the problem was.

[Jeffy]

Was finally able to view the pics.  The surfaces should be smooth to the touch.  Looks like there's still some stuff where the temp. sensor passage is.  From Pic #2 it looks like there wasn't any RTV on the bottom half of the gasket.  There's no signs of blue down there.

Here are some pics when I was checking my thermostat.  I think I tighten the thermostat housing to 20-25lbs since that's the lowest my main torque wrench goes to.