To Hell with the FMS thermostat housing!

[trueblue01]

I'm so over this pos! It leaked from the get go but not bad. I think between the chrome and the shoddy craftsmanship it sucks. I've had it for a little over a year and took it off once because the leak was getting worse. So i put a new gasket and figured while i'm at it i put a mr. gasket thermostat in. That was in september and it already failed. It was stuck shut. I replace it and the damn housing leaks like crazy. It turns out its warped beyond recognition. So i didn't feel like spending $100+ on a decent one so i decided to clean up the factory one. I was impressed! A couple of hours later and behold:

View attachment 330483

 

[SVT32VDOHC]

Yes....my friend has one on a 1995 Mustang GT. His leaked from the day he put it on and it is still leaking. Your OEM one looks great.

 

[Demented4.6]

mine has been on my 88 for 6 years without a single problem. maybe they changed their casting

 

[iwashmycar]

my brother got one for his 94 that leaked like crazy, but the one on mine has worked out great. its all the luck of the draw..

also.... damn good job there

 

[Fett]

I have heard a few people had leaking issues. You can use diesel silicone (grey), that might solve the problem. Apply a thin layer to the intake and a thin layer to the housing, let sit for a little while until it starts to dry slightly, then put the housing on.

I sealed an external waterpump housing like this and it hasn't as much seeped a drop in 5 years.

 

[capri debris]

1. Put a small amount of RTV on the edge of the themostat, place it in the housing and let it set up for a few hours. This will keep the t-stat from moving when you install the housing. (this is the reason for MANY leaks... if the t-stat shifts, it will cause a gap and a leak is certain)

2. Spread some RTV on BOTH sides of the gasket.

3. Install the housing and draw the bolts down a little at a time going back and forth on each one so you don't warp it.

Do it this way and you'll never have a leak. Stop blaming the housing... I've yet to have a leak with any of the housings I've used (chrome ones too) and I've been building engines since I was 18 and I'm 42 years old.

 

[Ozz]

Polish the stocker

I've heard tons of horror stories about those chrome ones for some reason, and I'm glad I was always too lazy to get one before I started hearing those stories.

 

[85_SS_302_Coupe]

I did an intake swap once and was 20 miles from home and had to drive my car home...it was late at night and i didn't have any gaskets, just RTV. I got desperate and cut out a gasket from a Coke 12 pack box. Used RTV on both sides and on the inside edge of the thermostat.


It's been on there for a good year now with no leaks

 

[Darkwriter77]

I think it was Daggar that recommended to me just taking a drop or two of Super Glue to the thermostat to hold the thing in place while you're fiddling around with the gasket. Sets up a helluva lot quicker than waiting for HOURS for RTV to set up and cure.

In the past, I've always had luck with simply putting the T-stat into the housing, then sliming some RTV on there, pressing the gasket onto the housing (making sure the bolt holes line up, of course), and waiting about 30 minutes so it stays tacky enough to hold the gasket in place fairly well while you manipulate the little turd into position. Not as exact or reliable, but again, it's always seemed to work just fine for me. (Although I now prefer the Super Glue trick. )

 

[iwashmycar]

now that i think of it i did have the upper radiator hose slide off on the interstate...that sucked....the chrome made for a slippery surface to tighten down on..

 

[grey5.0beast]

One time after my explorer intake install I was trying to hurry up and pickup my GF for her Bday dinner. I was in a huge rush and when I pulled the tstat b/c it was leaking, the gasket ripped in half. I slabbed a bunch of RTV on it, put half of the gasket back on and let it sit for about 5 min before I had to pick her up. It worked fine for about 11 months, I am going to replace it while it is off the car now, but it held the whole time

 

[pistonhead351]

I use super weatherstrip adhesive to hold the thermostat in place while im trying to put it on. Sets up in minutes and comes off easy with a wire wheel.

 

[Deleted member 87397]

I don't remember exactly what I did last time. I put in a Mr. Gasket 185 stat and a CSR billet aluminum housing. Haven't had a bit of trouble with it for over 2 years now.

 

[NIKwoaC]

dude, I dunno about you guys, but just buy the gasket that has the adhesive backing on it from NAPA... makes holding the thermostat and gasket in place a snap while you install the housing.