Leaking thermostat housing

95Cobra302

Founding Member

Apr 9, 2002

394

3

19

Daytona Beach, FL

Dec 18, 2007

#1

• Dec 18, 2007

• #1

I picked up a chrome FMS thermostat housing awhile ago and threw it on, even though I heard of all the troubles some people on here have had with them. It just started leaking and I'm wondering if anyone has found a fix to it or should I just paint the original one and put it back on???

 

Stanger007

Founding Member

Sep 26, 2001

2,015

2

46

Baton Rouge, LA

Dec 19, 2007

#2

• Dec 19, 2007

• #2

One thing I always have trouble with when putting a thermostat housing on is trying to keep the thermostat seated in the housing and not letting it slip between the intake and the housing.

A few tricks I've learned:

1. Only use a thin film of RTV on both sides of the thermostat gasket.
2. Get the sealing surfaces surgically clean with a razor and some brake cleaner on a rag.
3. Use a dab of some black or hi-tack RTV to keep the thermostat seated in its groove while installing.
4. Get a thermostat gasket with an adhesive side (made just for this reason).
5. Put thread sealant on the housing bolts that go into the water.

Good luck!
Wes

 

wythors

Get off my lawn!!!

Founding Member

May 17, 2000

2,277

35

69

C Addle

Dec 19, 2007

#3

• Dec 19, 2007

• #3

Over the years I've tried two different FRPP chrome t-stat housings. I was never able to get the big bolt head thingy on either one to seal completely. I tried teflon tape, plumber's putty and even putting an o-ring under it. It always seeped, no matter what. I finally took off the second one and polished up my old one. Good nuff.

 

R

red95gtconvert

New Member

May 29, 2006

382

0

0

Ponca city, OK

Dec 19, 2007

#4

• Dec 19, 2007

• #4

Stanger007 said:

One thing I always have trouble with when putting a thermostat housing on is trying to keep the thermostat seated in the housing and not letting it slip between the intake and the housing.

A few tricks I've learned:

1. Only use a thin film of RTV on both sides of the thermostat gasket.
2. Get the sealing surfaces surgically clean with a razor and some brake cleaner on a rag.
3. Use a dab of some black or hi-tack RTV to keep the thermostat seated in its groove while installing.
4. Get a thermostat gasket with an adhesive side (made just for this reason).
5. Put thread sealant on the housing bolts that go into the water.

Good luck!
Wes

Click to expand...

That is how I do it and have never had one leak ever, there is some good advice offered in that post, that or ditch the FMS cover. As soon as I read your thread title I knew it was the infamous leaky chrome cover lol.

 

Wi Stang

Member

Jun 27, 2004

248

0

16

Fountain City, WI

Dec 19, 2007

#5

• Dec 19, 2007

• #5

I vote for cleaning up the old housing and painting it. That is the route I went.
I tried, tried, and tried again to get the FMS chrome housing to seal with no success.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

33

129

Dec 19, 2007

#6

• Dec 19, 2007

• #6

Have you checked the housing's edge for plumb?


Wes's post was excellent. Another way of keeping the stat from dropping out involves looping a string through it and back out the housing's hose bung. Just keep the string taut.

 

95strokerPSU

Member

Jul 29, 2004

986

1

19

Sacramento from Philly

Dec 19, 2007

#7

• Dec 19, 2007

• #7

I've had luck using two gaskets and re-torquing the bolts after the first couple heat cycles. You might also want to put it on a glass table and find out where it is warped. You might be able to sand it down to get it to sit flush.

Good Luck

 

Bosko5.0

Active Member

May 18, 2006

1,067

0

37

longwood, FL

Dec 19, 2007

#8

• Dec 19, 2007

• #8

Jt thats how I did myne. also used the gasket with rtv on both sides.

 

StadEMS3

20+ Year Stangneter

Jun 19, 2003

228

43

49

Mechanicsville, MD

Dec 19, 2007

#9

• Dec 19, 2007

• #9

I went threw two of them myself and was unable to stop the leaks. You would think FMS would redesign the thing I ended up getting one from autozone with the removable plug for the autometer gage temp sensor. I cleaned up all the casting flash and powder coated it myself with reflective chrome. Looks good, no leaks.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

33

129

Dec 19, 2007

#10

• Dec 19, 2007

• #10

StadEMS3 said:

I ended up getting one from autozone with the removable plug for the autometer gage temp sensor.

Click to expand...

I would not use this port for your accurate temp gauge. If the stat sticks closed, the gauge will not relate accurate engine temps to you.
I put the stock sender in the stat housing and the aftermarket gauge sender in the stock sender location on the intake manifold.

 

StadEMS3

20+ Year Stangneter

Jun 19, 2003

228

43

49

Mechanicsville, MD

Dec 20, 2007

#11

• Dec 20, 2007

• #11

I put the stock sender in the stat housing and the aftermarket gauge sender in the stock sender location on the intake manifold.

Good call, I'm gonna put that on my winter "todo" list.