Thermostat

[Omathisen]

Changing the thermostat on a 351W - have the gasked for the wateroutlet. Old thermostat also had a sealant on it. Any recommendations and do I put the sealant on both the thermostat against the housing and on the gasked?
Thanks.
OMathisen
ERA

[Tim Brewer]

Don't put sealant on the thermostat itself. Just a little on the thermostat housing gasket.

[SuperHart]

ANother point when replacing the thermostat is to drill a 1/8" hole in the top of the thermostat plate at the 12 o'clock position to help bleed air out of the intake manifold. Because the thermostat mounts vertically it is sometimes difficult to get the thermostat to stay in the groove while you mount the housing over it. What I do is mount the thermostat in the groove in the housing with a couple of tiny dabs of silicone sealer to keep it in place. Then I apply the gasket to the thermostat housing with a thin bead of silicone and then apply the assembly to the intake manifold with both bolts in place. Not applying silicone sealer to the intake side of the gasket makes future removal easier. IMHO, the easiest way is to use a thermostat housing that uses the rubber O-ring gasket. No sealer required at all and very easy future removal. I have never had a leak with the O-ring gasket.

[Carnut427]

Let's see what kind of discussion we get from this...I don't use gasket sealer on most gaskets..the exceptions are around the water holes in intake gaskets, I use silicone only for the front & rear of an intake, and use silicone when assembling the rear main & front cover to pan corners, that's about it. Oh, and I use silicone to "glue" the thermostat to it's housing the night before I'm going to install it. Broken more than one housing because the thermostat wasn't in the groove. As for the rest of the gaskets, as long as the surfaces are smooth enough, I let the gasket do the job, and haven't had any problems in years. This idea was passed on to me by a guy who worked in a garage and I was working at an auto parts store while in high school. I asked why he didn't use gasket sealer, and his reply was "do you want to have to remove it?" Of course, we always pushed gasket sealer at the store, but I slowly tried doing things "his" way, and like I said, the gasket will do it's job.

Dan

[Ibr8k4vetts]

"I use silicone only for the front & rear of an intake, and use silicone when assembling the rear main & front cover to pan corners, that's about it."
And bolts that go in to water jackets

[Excaliber]

I agree Carnut427, mostly I rely on the GASKET to do it's job (and yes, on the bolts into water jackets).

Even when I do use silicone (intake front\rear, etc) I'm very careful to use only enough to do the job. I don't want the excess 'floating' around in the engine somewhere.

[Omathisen]

Hi,
I used a little silicone to hold the thermostat in the housing/water outlet and a little on the gasket. So far, no leak.
Thanks.
OMathisen