Thermostat Housing Leak
Thread Starter
Instructor
Joined: May 2018
Posts: 248
Likes: 11
Thermostat Housing Leak
I have an Edelbrock Performer intake with an chrome aluminum aftermarket Thermostat Housing. The oring was causing a leak so I bought a paper gasket and reinstalled using a sealer ...no luck. I discovered the heater hose was bad so I replaced it with a new Thermostat Housing Gasket. Well the housing is leaking again. All I can firure is that the gasket has 2 oblong holes and it keeps shifting to the wrong position. Mr. Gasket makes several different types but not sure which one to purchase.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
You are correct. Mr. Gasket makes a wonderful gasket for water-necks. Its silicone. Its orange. Its reusable. It seals well.
Much better than a 2 cent paper unit.
But. It's around $25. Yikes !!! Did I mention it's reusable. For years & years & years.
You can look at them on Summit Racing. Then figure out if it's sold locally or not.
Those silicone units are normally installed dry. But some people smear a sealant on there anyway, both sides.
Make sure your water-neck bolts are not bottoming-out, common issue. Install both bolts w/o the housing and just snug them. Place the housing next to the bolts for measurement.
Also. a light sanding of the bottom of the water-neck assures its flat, level and smooth.
On the snout of the water-neck, I rough-up the chrome with sandpaper. Then I smear a Glycol-proof sealant on the snout just before installing the Rad hose.
Several sealants do not do well with Glycol. Permatex makes a tube of sealant specifically called: Water pump / Water neck sealant. (AutoZone $7)
Don't let people tell you to throw the chrome housing away. You can get an excellent seal if you know how.
<<<<<<<<<<<<<< The picture to the left is proof. Eddy Intake & Chrome water-neck.
Much better than a 2 cent paper unit.
But. It's around $25. Yikes !!! Did I mention it's reusable. For years & years & years.
You can look at them on Summit Racing. Then figure out if it's sold locally or not.
Those silicone units are normally installed dry. But some people smear a sealant on there anyway, both sides.
Make sure your water-neck bolts are not bottoming-out, common issue. Install both bolts w/o the housing and just snug them. Place the housing next to the bolts for measurement.
Also. a light sanding of the bottom of the water-neck assures its flat, level and smooth.
On the snout of the water-neck, I rough-up the chrome with sandpaper. Then I smear a Glycol-proof sealant on the snout just before installing the Rad hose.
Several sealants do not do well with Glycol. Permatex makes a tube of sealant specifically called: Water pump / Water neck sealant. (AutoZone $7)
Don't let people tell you to throw the chrome housing away. You can get an excellent seal if you know how.
<<<<<<<<<<<<<< The picture to the left is proof. Eddy Intake & Chrome water-neck.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Take a sticky back 80 grit DA sander disc and stick it to a flat surface (granite stone, flat aluminum block, etc.....) and run the water neck in a figure 8 pattern sanding the o-ring/gasket surface.....do this a LOT...then do it some more......you will see the chrome being sanded away and witness marks where it isn't flat....they are ALL like this......
Now find another o-ring and install it WITH the gasket dry......if the intake water outlet housing is in good shape, it will seal. You can use a SMALL amount of RTV to fill the groove in the water neck...but just enough to fill it.
I prefer the non o-ring necks and sand those flat.....they will seal with zero RTV everytime.
Any water neck I touch on an old car gets this treatment.....
Jebby
Now find another o-ring and install it WITH the gasket dry......if the intake water outlet housing is in good shape, it will seal. You can use a SMALL amount of RTV to fill the groove in the water neck...but just enough to fill it.
I prefer the non o-ring necks and sand those flat.....they will seal with zero RTV everytime.
Any water neck I touch on an old car gets this treatment.....
Jebby
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
You are correct. Mr. Gasket makes a wonderful gasket for water-necks. Its silicone. Its orange. Its reusable. It seals well.
Much better than a 2 cent paper unit.
But. It's around $25. Yikes !!! Did I mention it's reusable. For years & years & years.
You can look at them on Summit Racing. Then figure out if it's sold locally or not.
Those silicone units are normally installed dry. But some people smear a sealant on there anyway, both sides.
Make sure your water-neck bolts are not bottoming-out, common issue. Install both bolts w/o the housing and just snug them. Place the housing next to the bolts for measurement.
Also. a light sanding of the bottom of the water-neck assures its flat, level and smooth.
On the snout of the water-neck, I rough-up the chrome with sandpaper. Then I smear a Glycol-proof sealant on the snout just before installing the Rad hose.
Several sealants do not do well with Glycol. Permatex makes a tube of sealant specifically called: Water pump / Water neck sealant. (AutoZone $7)
Don't let people tell you to throw the chrome housing away. You can get an excellent seal if you know how.
<<<<<<<<<<<<<< The picture to the left is proof. Eddy Intake & Chrome water-neck.
Much better than a 2 cent paper unit.
But. It's around $25. Yikes !!! Did I mention it's reusable. For years & years & years.
You can look at them on Summit Racing. Then figure out if it's sold locally or not.
Those silicone units are normally installed dry. But some people smear a sealant on there anyway, both sides.
Make sure your water-neck bolts are not bottoming-out, common issue. Install both bolts w/o the housing and just snug them. Place the housing next to the bolts for measurement.
Also. a light sanding of the bottom of the water-neck assures its flat, level and smooth.
On the snout of the water-neck, I rough-up the chrome with sandpaper. Then I smear a Glycol-proof sealant on the snout just before installing the Rad hose.
Several sealants do not do well with Glycol. Permatex makes a tube of sealant specifically called: Water pump / Water neck sealant. (AutoZone $7)
Don't let people tell you to throw the chrome housing away. You can get an excellent seal if you know how.
<<<<<<<<<<<<<< The picture to the left is proof. Eddy Intake & Chrome water-neck.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
I was curious.
This is from Permatex official web site.
Ultra Black:
Automotive: Excellent sealing characteristics for oil.
Works well on Valve Covers, Oil Pans, Intakes china walls, Timing Covers and differential covers.
(no mention of water-necks / water-pumps)
Marine use: Valve Covers, Oil Pans, Intakes china walls, Timing Covers and Thermostat Housing / Water pumps.
So. What's the difference in applications?
One engine gets Glycol.
The other gets sea-water.
This is from Permatex official web site.
Ultra Black:
Automotive: Excellent sealing characteristics for oil.
Works well on Valve Covers, Oil Pans, Intakes china walls, Timing Covers and differential covers.
(no mention of water-necks / water-pumps)
Marine use: Valve Covers, Oil Pans, Intakes china walls, Timing Covers and Thermostat Housing / Water pumps.
So. What's the difference in applications?
One engine gets Glycol.
The other gets sea-water.
Melting Slicks
Joined: Feb 2018
Posts: 2,329
Likes: 725
From: Marietta GA
I just bought a new water outlet that included a new o ring, and the leak stopped . The new type water outlets, aka thermostat housings, come with o rings, probably because they are not perfectly flat!
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I've had a chrome housing with a rubber O-ring on my stock intake for years.
Sometimes usually after winter storage I'd spring a leak an I'd just replace the ring.
But last time I put a bead of Permatex OUTSIDE the O-ring & it hasn't leaked since...
Sometimes usually after winter storage I'd spring a leak an I'd just replace the ring.
But last time I put a bead of Permatex OUTSIDE the O-ring & it hasn't leaked since...
Team Owner
Joined: Mar 2002
Posts: 44,692
Likes: 1,834
From: Huntsville AL
I have has good luck with a Fel-Pro SFL35562T gasket.
https://www.jegs.com/i/Fel-Pro/375/35562T/10002/-1
https://www.jegs.com/i/Fel-Pro/375/35562T/10002/-1