Thermostat Housing LEAKS... any tips

White 89 · January 3rd, 2008, 11:15 AM

I just spent a few hours the other day replacing my waterpump. Since I had to replace the waterpump I thought what the heck I will replace all the hoses and thermostat. I got the car all put back together filled the rad. with coolant and I noticed a leak. I got under the car looked and looked and it was coming from the bottom of the theromstat housing. I was happy that is wasn't coming from the waterpump. So I took the thermostat housing back off. Which was a pain because the lower bolt on the right took 30 minutes to take off. It's hard to get to. I went to local parts store and bought a brand new housing. It came with a gasket.

Here is the question.

Is it housing theromstat then gasket

or

housing gasket then thermostat on top.

Also I used Permitex waterpump and theromostat housing gasket sealer.

Should I use RTV instead this time. Any tips for a better seal.

thanks

mdvaldosta · January 3rd, 2008, 11:30 AM

Use both gasket and type 2 RTV (the kind that's not gasket maker, it'll stay soft). Shouldn't leak then. Make sure the surfaces are clean of any stuck gasket material.

kuskye25 · January 3rd, 2008, 11:30 AM

Thermostat Install - StangNet - Promoting the Legend of the Ford Mustang

i couldnt remember off hand which way it goes i just put mine in the way it came out, but maybe this link will clear it up for you, for my waterpump ive never used gasket sealer just a gasket.

White 89 · January 3rd, 2008, 11:35 AM

On the waterpump I used Permatex. It was a silver color. I put a bead on the gasket and then spreaded it out with my fingers.

ryans88gt · January 3rd, 2008, 01:42 PM

Use ultrablack RTV and let it set up for an hour before you start the car. You really don't need a gasket at all.

GodFather aka Perky · January 3rd, 2008, 01:48 PM

* Place the thermostat on the housing with the spring side going towards the intake.
* Use a little gasket sealer (Permatex Blue is my preference) to help hold it in place while you are moving it.
* Put the gasket on AFTER the thermostat so the gasket will be touching the intake when installed. Use a little gasket seal to hold it all in place and make sure no leaks will occurs.
* Now, replace the thermostat housing and the bolts, tightening them together so as to not cause the thermo to squeeze to one side and you should have a nice snug fit.
* Let the sealer "cure" for recommended time before starting her up.

jam77 · January 3rd, 2008, 03:09 PM

just like ryan said the black rtv works awesome

JBIGBOOTSY · January 3rd, 2008, 05:31 PM

I just use RTV and apply it, start the bolts till there is ~1/8" gap wait an hour, then snug it tight.

drifts14x · January 4th, 2008, 09:33 AM

I used the blue stuff and a new gasket as well...on my 3rd try.

It's really important to let the gasket set up. I tried to crank right after I got it all back together twice and it leaked like a faucet.

stang94 · January 4th, 2008, 10:43 AM

I had the same problem, I went back in, took out everything, toss the gasket and user the ultrablack RTV, and never saw a leak again, until the car was total

You have to give it some time let it dry before you, start the car. Just get it from autozone, read the instructions and you'll be fine.

White 89 · January 7th, 2008, 10:29 AM

SUCCESS

I used RTV Blue stuff. I went around all the bolts put a little extra. I let the glue set up for over an hour. Then filled the antifreeze up and no leak. I was happy.

JBIGBOOTSY · January 7th, 2008, 10:52 AM

Yea!

e3sean · January 7th, 2008, 11:42 AM

glad to hear you got it..in the future the black high temp it the best you will never worry about it failing

January 3rd, 2008, 11:15 AM	#1
White 89 Regular Join Date: Oct 2007 Posts: 273	Thermostat Housing LEAKS... any tips I just spent a few hours the other day replacing my waterpump. Since I had to replace the waterpump I thought what the heck I will replace all the hoses and thermostat. I got the car all put back together filled the rad. with coolant and I noticed a leak. I got under the car looked and looked and it was coming from the bottom of the theromstat housing. I was happy that is wasn't coming from the waterpump. So I took the thermostat housing back off. Which was a pain because the lower bolt on the right took 30 minutes to take off. It's hard to get to. I went to local parts store and bought a brand new housing. It came with a gasket. Here is the question. Is it housing theromstat then gasket or housing gasket then thermostat on top. Also I used Permitex waterpump and theromostat housing gasket sealer. Should I use RTV instead this time. Any tips for a better seal. thanks __________________ 1989 mustang GT 5.0

January 3rd, 2008, 11:30 AM	#3
kuskye25 Regular Join Date: Dec 2007 Posts: 356	Thermostat Install - StangNet - Promoting the Legend of the Ford Mustang i couldnt remember off hand which way it goes i just put mine in the way it came out, but maybe this link will clear it up for you, for my waterpump ive never used gasket sealer just a gasket. __________________ '88 Mustang GT, Long Tube Headers, Off Road H-pipe, Flowmasters w/turn downs, K&N, Under Drive Pullies, Smog delete/Ac eliminator/72" belt, Subframe connectors, 3.73 Gears '93 LX 4-banger 78k miles

January 3rd, 2008, 11:35 AM	#4
White 89 Regular Join Date: Oct 2007 Posts: 273	On the waterpump I used Permatex. It was a silver color. I put a bead on the gasket and then spreaded it out with my fingers. __________________ 1989 mustang GT 5.0

January 3rd, 2008, 01:42 PM	#5
ryans88gt MM Fanatic Join Date: May 2007 Location: Bloomington, IL Posts: 3,322	Use ultrablack RTV and let it set up for an hour before you start the car. You really don't need a gasket at all. __________________ 89 LX 515 hp 497 ftlbs 88 GT 11.4 @ 118

January 3rd, 2008, 01:48 PM	#6
GodFather aka Perky Newbie 1988 Mustang LX coupe Join Date: Jan 2008 Location: MotorCity, Michigan Posts: 33	* Place the thermostat on the housing with the spring side going towards the intake. * Use a little gasket sealer (Permatex Blue is my preference) to help hold it in place while you are moving it. * Put the gasket on AFTER the thermostat so the gasket will be touching the intake when installed. Use a little gasket seal to hold it all in place and make sure no leaks will occurs. * Now, replace the thermostat housing and the bolts, tightening them together so as to not cause the thermo to squeeze to one side and you should have a nice snug fit. * Let the sealer "cure" for recommended time before starting her up. __________________ '88 White 5.0 Coupe - AOD w/shift kit w/stock cam - Typhoon intake, Edelbrock hds (1.90/1.60), Crane 1.7 rollers, 76-mm MAF, 70-mm TB, polished VCs, 4.10 gears. Coming soon...Hi-stall converter, mod VB, XE264HR cam and TMoss ported Explorer intake.

January 3rd, 2008, 11:30 AM	#2
mdvaldosta Maintenance Man 2002 Mustang GT 11.47@120.58 Join Date: Aug 2005 Location: Valdosta, GA Posts: 3,928	Use both gasket and type 2 RTV (the kind that's not gasket maker, it'll stay soft). Shouldn't leak then. Make sure the surfaces are clean of any stuck gasket material.

January 3rd, 2008, 03:09 PM	#7
jam77 Enthusiast 1987 Mustang GT Join Date: Apr 2007 Location: IL Posts: 685	just like ryan said the black rtv works awesome __________________ 87 GT, typhoon upper and lower,70mm tb, 90mm maf, bbk shorties, bbk x-pipe, flowmaster cat back, 3:73 gear, pro 5.0 shifter, novi blower,afm power pipe, load IO, Trick Flow heads, Anderson B-31 cam, Anderson PMS, 42 lb injectors, t-rex fuel pump.

January 3rd, 2008, 05:31 PM	#8
JBIGBOOTSY Hardcore Enthusiast 1990 LX hatch Join Date: Aug 2006 Location: Hobart Indiana Posts: 1,803	I just use RTV and apply it, start the bolts till there is ~1/8" gap wait an hour, then snug it tight.

January 4th, 2008, 09:33 AM	#9
drifts14x Newbie Join Date: Jun 2007 Posts: 8	I used the blue stuff and a new gasket as well...on my 3rd try. It's really important to let the gasket set up. I tried to crank right after I got it all back together twice and it leaked like a faucet. __________________ 1995 Ford Mustang GT Vibrant Red w/ Black Cloth Interior K&N Drop-In Filter BBK Off-road H-Pipe Flowmaster 40 Series Exhaust MSD 8.5mm Pro Core Wires 245/45ZR17 Nitto NT-555 Extreme KYB GR-2 Struts and Shocks Ford Racing "F" Springs

January 4th, 2008, 10:43 AM	#10
stang94 Enthusiast Join Date: Oct 2006 Location: Jamaica, NY Posts: 972	I had the same problem, I went back in, took out everything, toss the gasket and user the ultrablack RTV, and never saw a leak again, until the car was total You have to give it some time let it dry before you, start the car. Just get it from autozone, read the instructions and you'll be fine. __________________ FREE & FOR SALE 198x 351W Block - 90,xxx Miles (FREE) 94-98 GT Hood, 2 pr tail light - 1 Pr power mirror - FREE NEW - ENERGY SUSP Motor Mount POLY, RED ($100) NEW - Reserve Glow Blue/Green ($50)

January 7th, 2008, 10:29 AM	#11
White 89 Regular Join Date: Oct 2007 Posts: 273	SUCCESS I used RTV Blue stuff. I went around all the bolts put a little extra. I let the glue set up for over an hour. Then filled the antifreeze up and no leak. I was happy. __________________ 1989 mustang GT 5.0

January 7th, 2008, 10:52 AM	#12
JBIGBOOTSY Hardcore Enthusiast 1990 LX hatch Join Date: Aug 2006 Location: Hobart Indiana Posts: 1,803	Yea!

January 7th, 2008, 11:42 AM	#13
e3sean Hardcore Enthusiast Join Date: Nov 2007 Location: arizona Posts: 2,638	glad to hear you got it..in the future the black high temp it the best you will never worry about it failing

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