Leaky thermostat housing

[mudbog42]

I have replaced the gasket on the thermostat housing about three or four times, put a new housing and it holds for a few months then begins to leak again. Happened this time when I drove back to Florida from Tennesee. Way up there it was fine. Any Ideas??

 

[rcamacho]

I've only had success with the nice thick cast iron thermostat housings. The aluminum/chromed/pot metal stuff is terrible. Other than using a gasket with perhaps some sealant, no problems.

 

[mudbog42]

I have one of the cast iron ones, i think, I got it from Kragen. If its not where could I get one?

 

[ryoken]

make sure your surfaces are flat... I like to drag a flat file over them and mill as nescessary... Use a sealant like Perfect Seal, Permatex #300, etc on both sides of the gasket... Do NOT use silicone...

 

[BoondocK5]

I always use permatex 2B it never hardens, works great with or without a gasket

 

[ryoken]

it never hardens

Nor do the ones I mentioned...

 

[4xcrazy]

you CAN use silicone, you just have to know how to use it

 

[ryoken]

Silicone sucks... Well, standard blue RTV sucks.. I should quantify that... The ultra black and some of the others are ok because they have more elastomeric rubber properties to them..

 

[JEBSR]

Is the intake pitted real bad or anything? Is it aluminum or cast? I have had pretty good luck with after market housings with a rubber O ring. Dont get the really cheap one like at autozone though go through jegs or summit. They have a couple quality ones. Also sounds like the intake could be warped as well I would try the trick ryoken was talking about as well

 

[mudbog42]

Is the intake pitted real bad or anything? Is it aluminum or cast? I have had pretty good luck with after market housings with a rubber O ring. Dont get the really cheap one like at autozone though go through jegs or summit. They have a couple quality ones. Also sounds like the intake could be warped as well I would try the trick ryoken was talking about as well

I was also thinking the intake could be warped. Its the original cast iron one that came with the truck so its 20 years old but I'll probably try what ryoken said first though then maybe get an edelbrock performer later when i save some money

 

[ryoken]

You'll know real quick if you drag a short file over it... It'll cut those high spots... They like to "pull up" at the bolt holes sometimes...

 

[diesel4me]

leaks suck...

I've had my share of aggravation with leaky water outlets on Chevy's too....its part of the ritual of owning one..!

In many cases the water outlet is hairline cracked,and it only leaks during overnight parking as it contracts or while warming up under expansion..this especially applies to the OEM die cast ones..

The "O" ring style do work better,but hope you wont need a new "O" ring if you have to replace it far from home or a speed shop...not your everyday common easy to find gasket really...

I used a rubber gasket made from an old inner tube on a 283 I had that defied my every effort to seal it(probably had a warped intake surface) ..it worked pretty good,but only lasted a year or so..never leaked a drop,then one day it started gushing..

I ended up using "Indian Head Gasket Shellac" made by Duro/Permatex,along with TWO usual thermostst gaskets.. --it sealed it for good,but I had to use a hammer and chisel to get the gasket off next time I changed it!..that stuff is like a weld in a bottle!..