Thermostat gasket sealant?

Status
Not open for further replies.
Joined
Nov 22, 2005
Messages
666
Location
Charlotte, NC
Replaced thermostat and gasket today. My dad says I need to rip it out again and throw some sealant on the gasket. Needed or not?

95 F150 5.8L
 
Is it leaking? No? You're okay.

I prefer sealant as a preemptive "problem solver" in case there's a nick in either surface. I hate draining fresh antifreeze cleanly and trying to reuse it, so I like getting it done right the first time.
 
I usually use the grey Motorcraft gasket stuff on either side of those as they can sometimes leak. But if it isn't leaking, don't worry about it.
 
I know some of them housing 's are plastic now an if ya overtorque em you'll crack em ain't no amount of sealant gonna fix it best bet don't break it n if its a metal one a gasket should do the trick I'ge done this a 1000 times I ain't never needed a sealer to do it an none never leaked less yer intake warped which wouldn't be the case Cu's I don't think you would run it around for days on end without any water in it?"
 
Originally Posted By: binkis
I know some of them housing 's are plastic now an if ya overtorque em you'll crack em ain't no amount of sealant gonna fix it best bet don't break it n if its a metal one a gasket should do the trick I'ge done this a 1000 times I ain't never needed a sealer to do it an none never leaked less yer intake warped which wouldn't be the case Cu's I don't think you would run it around for days on end without any water in it?"


The way the 2-bolt housing/gasket/flange mount is on the Windsor, both being aluminum, sometimes there's some pitting or corrosion that causes them to leak with just the gasket. The sealer fills the imperfections (or sometimes they are just warped too and the sealer gets around that) and ensures they don't leak.
 
Use the "Right Stuff" gasket maker lightly on both sides of gasket if leaking.
Flat sanding the housing and lightly flat filing the flange mount also help. Doubling the gasket works too.
 
On aluminum stuff I use Permatex 2 Non hardening Aviation forma gasket. as a gasket sealer. It is great. I once put a waterpump with blue RTV because I had messed up the gasket. Yrs later , I replaced the WP because the engine was going into another car.. I had to use the butt end of a 2x4 to pound it off the timing cover.
 
The gasket sealant makes the paper gasket waterproof. Keep an eye on it. If it
starts leaking, take the gasket back out and coat both sides with Permatex 2B.
 
Originally Posted By: oldhp
Use the "Right Stuff" gasket maker lightly on both sides of gasket if leaking.
Flat sanding the housing and lightly flat filing the flange mount also help. Doubling the gasket works too.


Flat sanding is a good idea on aluminum housings. We use to do this at the garage I worked at as a young man. We'd take some sandpaper, lay it face-up on a glass counter top (any glass would do, it's a good hard & flat surface). And then gently "orbit" the housing on the sandpaper. It was interesting how the ears would generally brighten first, revealing a subtle warping of the housing. After a bit of sanding, the entire face of the thermostat housing would brighten, indicating the housing face was flat.
 
Does it use an "o-ring" seal? In 355,000 miles and five thermostats my 89 Accord never needed any sealant applied to supplement the gasket. It had the type of rubber gasket that fit onto the the stat and had a raised o-ring profile at the edges.

Even on my 72 Pontiac, when I replaced the t-stat housing with an aftermarket chrome plated part that used an o-ring, I did not have to use sealant.

YMMV.
 
Originally Posted By: Rick in PA
Originally Posted By: oldhp
Use the "Right Stuff" gasket maker lightly on both sides of gasket if leaking.
Flat sanding the housing and lightly flat filing the flange mount also help. Doubling the gasket works too.


Flat sanding is a good idea on aluminum housings. We use to do this at the garage I worked at as a young man. We'd take some sandpaper, lay it face-up on a glass counter top (any glass would do, it's a good hard & flat surface). And then gently "orbit" the housing on the sandpaper. It was interesting how the ears would generally brighten first, revealing a subtle warping of the housing. After a bit of sanding, the entire face of the thermostat housing would brighten, indicating the housing face was flat.


I'd be surprised that he would be able to sand it flat, because many Ford t-stat housings have a small bead cast into them in the middle of the sealing surface.

Still, you do bring a good point that many housings can warp and leak.
 
Status
Not open for further replies.
Back
Top