theandies

I also suggest drilling 2 small holes in the t-stat will help get any air trapped out from taking the t-stat housing off.

DUB

with drilling a small hole in the thermostat itself.

It allows the trapped air to burp out of the engine block while it is running so you do not have to wait for the thermostat open when filling it.

And this small hole does NOT effect any of your cooling proprieties at all. So no fear of your engine all of a sudden beginning to overheat.

DUB

OzBeast

Couldn't you just fill the block with coolant through the thermostat opening before replacing the thermostat and housing? Then fill the radiator per normal.

Just wondering, I've never done it but I have heard of people filling the block directly, and if you've already got the thermostat housing off and replacing the gasket, why not?

I have a question similar to the OP, I'm fault finding a coolant leak and pulled my thermostat to check (it seems fine). Here in Australia I sourced the following gaskets and o-ring at my local auto parts store, but not sure if I should use sealant as well.

My housing has a groove for the o-ring, and I have a paper gasket as well which has adhesive on one side. The gasket sealant I bought is Permatex Fuel Resistant Gasket Sealant - 85420 as they didn't have the dedicated water pump/thermostat housing sealant.



Thoughts?

BLUE1972

Based on the pictures, I would just clean the housing and manifold - then grease the o ring with dielectric grease and assemble the water neck.

I have always drilled a 1/16 to 3/32" hole in the thermostat for 2 reasons:
1 - to get the air out
2 - to keep the water moving, it lessens the shock of a closed thermostat suddenly opening and especially with AL manifolds or heads reduces the temperature spike / shock. It does not affect the temperature of the motor.

HeadsU.P.

Dielectric Grease? Really? Thats for tail light / brake light bulbs and light sockets. I really doubt it will stand up to glycol and coolant inhibitors.

BLUE1972

YES, dielectric grease. It will not attack the O ring and it will allow it to properly seat. The grease is not for sealing.

That is the same reason it is recommended (by GM and other manufacturers) for the weather-stripping on the C3 T Tops, C4 - 5- 6 & 7 . It solved my squeaking when I run my C4 on a winding road / course. Solved the leak on my truck with the "chrome water neck" and now I can change thermostats without replacing the O ring.

leadfoot4

DUB

I guess you could if you wanted...But even when you fill the engine up and see coolant at the thermostat opening....there are air pockets in the cylinder heads.

If a person has a coolant leak....and it may not drip a drop of coolant but you are loosing coolant. That is the time when you obtain a coolant pressure tester and check you system INCLUDING your radiator cap!. I use my every time I get into the coolant system and I have found so many loose hoses that are high up on the system and will leak out pressure but no coolant.

DUB

DUB

X2 . I use dielectric on rubber 'O'-rings...such as the large 'O' ring for a fuel sending unit. No leaks.

DUB