Thermostat keeps leaking, help please!

[aldous]

Opps, wow, I was tired. Definitely a gasket not a filter....
Long day on the Jeep; and installed a new kitchen faucet too, before writing that...


So anyway, after I read all of the other threads on this, sounds like a new housing is not such a crazy idea. Not sure I have the skills to sand or file the existing one flat. For the time invested in trying that, a new one might be even-money.
Still curious about high flow options, there's only a little talk about them.

Joe Peters, f90 and others have pointed out throwing new bolts in there at the same time to be a wise investment. There's about 6 - 10 threads on broken bolts alone, sounds like a nightmare. I'm on my 5th Tstat install, so I know those bolts are probably getting tired.

The sizes for anyone else reading this are 5/16 18x1.5 upper and 5/16 18x.75 lower. Stainless Steel suggested with anti seize applied.

Another nifty tip I picked up was to raise the front of end of the XJ so as to not dump quite as much of my brand new coolant on the ground as I did on the last two go-rounds. In other threads a few were not aware that all of the coolant needed to be removed so that it was not lapping over the edge in order to be completely dry.


And before all that, still hoping the gasket might have swollen after it's been wet for 24 hours, there was a little bit of non definitive talk about that in another thread...

Thanks for all the help everyone.

 

[Dragonslayer]

Be absolutely sure that the thermostat stays seated in the head as you install the housing.

I changed my t'stat a few months ago and I actually saw the rascal shift ever-so-slightly
out of place as I was about put the housing over it.

 

[Ecomike]

You might want to tap and clean the bolt holes this time? Time to wonder if the bolts are running into junk and bottoming just before they tighten the gasket gap? I would use new bolts this time and a new housing, unless you are just having too much fun, LOL!

 

[RenegadeT]

I'm sure you ran silicone around the entire t'stat, but did you also loop a bead around the bolt holes?

 

[aldous]

Well much tado about nothing, it was indeed a cracked housing. It wasn't in the spot I expected, it was further up the body away from the bolt hole by an inch or two.

So I bought an aftermarket from AZ. Looking at it in the store I thought it fit perfectly, but once I got it on, there are some differences. I think flow to the heat hose is going to be cut some. But hopefully I'll be back on the road and it won't be that big of deal.

Also, important to note,
The bolts sizes I listed above are wrong. The thread I picked those up from might have referred to Renix? Mine on my 2001 are definitely not 5/16. My 1/2 seemed too small, and my 13mm seemed too large, so not exactly sure WTF they were supposed to be...Maybe not the end of the world to have different head sizes, but I don't know that mine are 18guage either, I just re-used the old ones.

I wish I could go back and edit that, but you don't allow that here.

And also, very important. In one of the threads I read, someone pointed out that the thermostat actually does need to be positioned with the bar going horizontally. If you put the thermostat in the housing and spin it, you will see that it does not work in all positions. In some positions, the bar pushes the tstat off center. This would be even more important for this go-round, since previously I just set it in the block on its indented resting point, and it probably would spin on it's own. This time, I rtv'd it in place to the block, and if I did not have it turned properly, the whole thing would not have worked. I don't have time to go back and check to see who that was that pointed it out, but it was only mentioned once in those dozens of threads, so if you're reading this, thank you sir...

 

[bigalpha]

And also, very important. In one of the threads I read, someone pointed out that the thermostat actually does need to be positioned with the bar going horizontally. If you put the thermostat in the housing and spin it, you will see that it does not work in all positions.

Interesting, I haven't seen this before.

 

[iwannadie]

I had an issue one time that took me a while to figure out.

When replacing the thermostat, all the coolant isn't drained from the head. There is a little bit of coolant that sits right below the thermostat opening. What was happening with me, was that little bit of coolant was seeping out and ruining the RTV or gasket. Once it was bolted up somehow the gasket or RTV acted as a wick and pulled the coolant up. I confirmed this by bolting everything up, not adding coolant and allowing the RTV to cure for a few hours before removing the thermostat housing again. I saw clearly where the coolant had dripped down the bottom of the opening ruining the seal even though when I assembled things the coolant was below the opening.

I used a pump(could just use paper towels) to get the coolant out of the head enough that it is not close to the opening, problem solved.

 

[Boostwerks.com]

Well much tado about nothing, it was indeed a cracked housing. It wasn't in the spot I expected, it was further up the body away from the bolt hole by an inch or two.

Told ya lol. I've seen probubly 5 or 6 with cracks. I highly reccomend to anyone that is going to replace their thermostat to replace the housing at the same time. Cheap insurance.

It's amazing how poor the casting was on those things. Glad you got it sorted out tho. :thumbup:

 

[norm09]

To clarify on the bolt sizeing when they say 5/16 by 18 by 1.5 they mean the width of the threaded part is 5/16 in diameter 18 is the threads per inch and the 1.5 is bolt length it has nothing to do with the tool size required for the bolt... Seemed like you might of been a little confused about that

 

[aldous]

To clarify on the bolt sizeing when they say 5/16 by 18 by 1.5 they mean the width of the threaded part is 5/16 in diameter 18 is the threads per inch and the 1.5 is bolt length it has nothing to do with the tool size required for the bolt... Seemed like you might of been a little confused about that

lol, now you know why I try to hire some of this stuff out...
Anyone need any marketing help