Thermostat sealing

[mr calais 5.0]

First off sorry if this is not the right place for this post.. I'm having trouble sealing the thermostat housing.. I broke the bolt off and drilled it out and put a heli coil in and new thermostat and gasket in and it sealed great and now is just weeping a little and it annoys me now.. Whats the stuff to use to seal it? I have tried permatex and didn't dork ad then saw my mechanic and he gave me the black silicone stuff and it sealed but now it weeping.. Should I just live with it or is there something else better?

[Brett_jjj]

Id just replace the thermostat gasket and not use any sealant on it.As long as the snapped off bolt that you fixed can tighten up as tight as the original one did, which is 20-27 Nm for a V8,then it should seal up fine..

[mr calais 5.0]

Cool thanks for the torque info. I just done it hand tight and not super tight cos I was a bit worried about breaking another bolt.. Will get the torque wrench out tomorrow and have a go..

[mr calais 5.0]

got the torque wrench out and nipped them up and seems to be good again.. just a bit paranoid about breaking more bolts i think too.. thanks heaps for your help

[EDGE3]

If it ends up weeping again you might need to get a new housing or a second hand one,and the problem with the gaskets is you cant over tighten the housing otherwise it will damage the gasket

[mr calais 5.0]

Nipped it up and then had to go to ringwood and back and no leaks or weeping..

[EDGE3]

Good work mate

[cander24]

Looks like you've got it sorted now, but if it leaks again i'd be doing 2 things. Use a non-hardening gasket sealant or hylomar gasket spray with a new gasket and also dress the bottom of the alloy thermostat housing. With age the alloy casting tends to distort a little, no longer giving a 'true' flat mating face and relying on the thickness of the gasket to take up any irregularities. This can be dressed on a sheet of say, 400 grit wet and dry sandpaper on a perfectly flat surface by rubbing the housing back and forth on it.

[mr calais 5.0]

just started to weap again.. getting annoyed with the car now.. Got the housing off and put it flat on a bench and it flat and even so my next quess is the manifold is not flat where the housing sits..Its not weaping heaps but the green stains from the coolant is weaping out and just damp.. might get another gasket and some of the other sealant and try again.. might see if i can find a thermostat thats less heat/preassure and see if that helps..I got the stock temp last time..