tstat gasket replacement question -- which way is up?

[barrys]

I'm probably going to replace my thermostat. I've seen gaskets with a raised seal on one side and read in the manual about applying rtv. With the gasket, would the seal go up towards the housing?
If I use one with no seal and apply rtv, would that only go on one side or both?

 

[Rearanger]

Seal toward the cover side. Why RTV? I've never used (or needed) RTV with a therm gasket. Which manual says use RTV?

 

[Explorin94]

That should have an "O" ring gasket. If they gave you an actual gasket that is fine but the "O" ring is alot better. Like Rearanger said...never use RTV on a tstat if you put it on too thick it can lodge in the tstat and hold it open or hold it closed. If you need to used anything get some aviation gasket. That will let the gasket stick to the housing so you can put it on.

 

[modelageek]

I'm probably going to replace my thermostat. I've seen gaskets with a raised seal on one side and read in the manual about applying rtv. With the gasket, would the seal go up towards the housing?
If I use one with no seal and apply rtv, would that only go on one side or both?

I would get a motorcraft if possible and if not make sure you get one that is oem compatible.........there are some junky tstats out there

 

[McCormack]

Some parts stores offer self-stick t-stat gaskets, and I've found them to be easier to use than regular gaskets... put the t-stat in the housing, stick the gasket to the housing, and the gasket will then hold the t-stat in as you lower the housing onto the manifold.

 

[barrys]

Those are all great responses.
> Which manual says use RTV?
That's a really good question. Chiltons and Haynes say "use rtv" with no explicit instructions. The HELM factory Ford manual does call out rtv. Glad you asked.

The instructions from the non-Helm manuals and seeing one of those "o-ring gaskets" online made me think that needs to be sealed with more than the gasket which is why I asked.

I think I'm going to just "be a good kid" and use Motorcraft parts and follow the good manual.

Also, does almost everyone drill that 1/16" hole in their thermostats? I'm thinking that if I get the Motorcraft tstat, it will either have the hole or not and I'll just install what I get.

 

[McCormack]

I've never drilled the 1/16" hole and I've never had a problem. You shouldn't really need RTV or an O-ring - clean the surfaces and pop a regular gasket in there and you should be good to go.

 

[Rearanger]

Also, does almost everyone drill that 1/16" hole in their thermostats? I'm thinking that if I get the Motorcraft tstat, it will either have the hole or not and I'll just install what I get.

Tstats will all have a bleed (by-pass) hole (or should) or a jiggle valve , even the aftermarket ones to allow air venting. Stant uses a bleed hole but it is so small you have to look for it. 1/16" is probably way too big. Also pay attention to how the bleed hole needs to orientated. On horizontal installations it is at the 12 o'clock position.

 

[Jason_J]

FSM does not call for gasket sealant, many people over use the crap and it breaks off and causes problems. One question, is it your 2010 that needs a new t-stat? Interesting that it would go out so fast, not to mention it would be under warranty.

 

[barrys]

That was a question about the 94. It's someone else's t-stat now.

 

[Big Jim M]

Sealant

There are only a few places on an engine that MIGHT need sealant of any kind. The thermostat housing isn't one of them.

Paper type gaskets need a CLEAN DRY place to sit. The paper adhears to the CLEAN DRY engine parts and never needs sealant.

The trick to getting the housing to NOT leak is to scrape all the old gasket off of it before reinstalling.

The places that MIGHT need sealant would be the CORNERS of most oil pans and the same corners of SOME intake gaskets.

When installing SOME valve covers I use a very small amount, small dabs the size of a match head, to stick the gasket to the cover before installing. This holds the gasket in place while fitting it in place. THIS sealant has nothing to do with SEALING!

Big JIm