I have a leak at the seal on the thermosat housing where it mates with the block. Should I use a gasket or just use RTV sealent? Think I saw a post somewhere along the line whether to use a gasket it or not.

Thanks

 

I'm using a gasket, no rtv. No leaks

 

i use a gasket, with a light coat of rtv on both sides, including around the bolt holes. if you haven't already done so, grind off the "front" tab. it makes it easier to get in/out in the future. i think those bolts go down into the water area in the manifold, so i put rtv on those threads too. don't over-torque.

 

I just changed my tstat. I used a gasket and no rtv and it leaked like a bitch.

You have to make sure both surfaces are REAL clean and dry. Put some rtv on the block. Then gasket, then rtv on the pipe. Also, take the hose off the pipe. Alternate tightening the the bolts until they're torqued down.

 

Word to the wise: The neck is SLIGHTLY angled, so be absolutely certain when changing the t-stat and reinstalling the neck that it's positioned properly to angle toward the radiator.

 

+1 thats how I do it

 

I also ended up using a 'cigarette paper thin'
coating of Blue RTV
on both sides of the gasket
and then letting it set up overnight
before re-starting the engine and putting pressure on it.

The official FSM instructions say to take loose the 13 bolts
that hold the accessory bracket in place
so that you can easily get at the T-sat flange to clean it off
and get the hose nipple back on squarely.

Like most I had originally tried to do the job 'down in the hole'
without removing those 13 bolts.

After three times doing it down in the hole
(i have fixed two that have gone bad, plus tried 180 & 205 versions)
I tried it the official FSM way and found it was not more time consuming,
plus you get to inspect the little rubber 'bypass hose'

 

For those of you that used the gasket for your thermostat, the only reason that it leaked was the fact that you didnt get the thermostat seated properly. When I changed mine, it leaked real bad to, but the thermostat on our trucks are really bad about getting knocked out of position when you put the neck back on. Just take your time and dont get in a hurry the gasket will work just fine.

 

Adding my voice to the chorus, use a gasket. The only time I won't use a gasket is in an emergency.