#1  
Old 03-28-2024, 11:13 PM
JEC3039 JEC3039 is offline
Member
 
Join Date: Jan 2016
Location: South Lyon, MI
Posts: 43
Default Fel-Pro T'stat Housing Gasket Wicking Itself to Death

On my last couple of engine builds I used the blue paper t'stat housing gasket that comes in a Fel-Pro engine gasket kit, and in both cases coolant wicked through the gasket and left a little pool on the valley cover. Upon removing the housings, the gaskets were soaked solid and literally fell apart in my hands. I don't understand what has changed and/or why Fel-Pro wouldn't use a material that resists self-wicking, but it is what it is I guess. I don't plan to use anymore of those again.

Has anyone found a gasket that doesn't wick and bleed out?

I see Butler has a gasket that looks like the original shape of a GM gasket (I have one NOS gasket of that shape and it is made of a waxy dark brown paper material). I'll call them tomorrow and ask about that one.

Any other recommendations would be welcomed.

  #2  
Old 03-29-2024, 03:30 AM
nUcLeArEnVoY's Avatar
nUcLeArEnVoY nUcLeArEnVoY is offline
Senior Member
 
Join Date: Sep 2021
Location: Homestead, FL
Posts: 183
Default

Used both. The butler gasket wicked, too. Not sure what it is about the thermostat housing gaskets.

I eventually just used a 1/8" bead of straight RTV w/ no gasket (Permatex has a purpose-made Waterpump and Thermostat Housing RTV), which is what the factory service manual even recommends doing for my car. Not a drop since.

__________________
1979 Trans Am W72 400/4-Speed WS6 - Starlight Black Hardtop
The Following User Says Thank You to nUcLeArEnVoY For This Useful Post:
  #3  
Old 03-29-2024, 11:32 AM
78w72 78w72 is offline
Ultimate Warrior
 
Join Date: Nov 2007
Location: iowa
Posts: 4,718
Default

You can use a thin layer of gasket sealer/maker to stop wicking on the paper type gaskets, thin bead of ultra black or grey spread out with your finger on both sides.

Ive been using the chrome T-stat housings with an O-ring for 20+ years that work great, no leaks and can be reused many times. If/when the oring flattens out, just buy a new one at a hardware store for a dollar. Might not look factory correct but for many cars with chrome/aluminum parts, factory correct doesnt matter.

  #4  
Old 03-29-2024, 06:06 PM
Goatracer1 Goatracer1 is offline
Ultimate Warrior
 
Join Date: Oct 2003
Location: NH
Posts: 3,792
Default

RTV sealer works great if you give it plenty of time to dry. Not just a few hours.

  #5  
Old 04-01-2024, 03:51 PM
ZeGermanHam's Avatar
ZeGermanHam ZeGermanHam is offline
Ultimate Warrior
 
Join Date: Nov 2016
Location: Seattle, WA
Posts: 1,927
Default

Quote:
Originally Posted by 78w72 View Post
You can use a thin layer of gasket sealer/maker to stop wicking on the paper type gaskets, thin bead of ultra black or grey spread out with your finger on both sides.

Ive been using the chrome T-stat housings with an O-ring for 20+ years that work great, no leaks and can be reused many times. If/when the oring flattens out, just buy a new one at a hardware store for a dollar. Might not look factory correct but for many cars with chrome/aluminum parts, factory correct doesnt matter.
This is what I do. Very thin film of Ultra Black RTV on both sides of the paper gasket. Zero leaks, zero seeping or sweating.

__________________

1966 Pontiac GTO (restoration thread)
1998 BMW 328is (track rat)
2023 Subaru Crosstrek Limited (daily)
View my photos: Caught in the Wild
The Following User Says Thank You to ZeGermanHam For This Useful Post:
  #6  
Old 04-01-2024, 04:26 PM
nUcLeArEnVoY's Avatar
nUcLeArEnVoY nUcLeArEnVoY is offline
Senior Member
 
Join Date: Sep 2021
Location: Homestead, FL
Posts: 183
Default

Quote:
Originally Posted by ZeGermanHam View Post
This is what I do. Very thin film of Ultra Black RTV on both sides of the paper gasket. Zero leaks, zero seeping or sweating.
I used Optimum Gray on both times I tried paper gaskets and it weeped. I doubt it was the different kind of RTV I used, so I guess maybe my mating surfaces have too much pitting? Didn't look like it last time I had it all apart but I still use the original cast iron intake and 'stat aluminum housing.

__________________
1979 Trans Am W72 400/4-Speed WS6 - Starlight Black Hardtop
  #7  
Old 04-01-2024, 04:45 PM
bhill86's Avatar
bhill86 bhill86 is offline
Chief Ponti-yacker
 
Join Date: Jul 2021
Location: NW Ohio
Posts: 529
Default

I too use the chrome neck with an o ring. I believe I tried RTV in the past on the paper gasket. The chrome isn’t my favorite looking (although not that bad) but it has sealed the best and as mentioned is reusable.

__________________
1977 Trans Am 400/4speed (swap)

Brian
The Following User Says Thank You to bhill86 For This Useful Post:
  #8  
Old 04-01-2024, 09:18 PM
4dblnkldude's Avatar
4dblnkldude 4dblnkldude is offline
Ultimate Warrior
 
Join Date: Oct 2006
Location: levittown
Posts: 1,868
Default

The right stuff spread out with your finger.... done start it up. I noticed this too.

__________________
" Is wearing a helmet illegal" Mike Kerr 1-29-09
  #9  
Old 04-02-2024, 11:10 AM
78w72 78w72 is offline
Ultimate Warrior
 
Join Date: Nov 2007
Location: iowa
Posts: 4,718
Default

Quote:
Originally Posted by nUcLeArEnVoY View Post
I used Optimum Gray on both times I tried paper gaskets and it weeped. I doubt it was the different kind of RTV I used, so I guess maybe my mating surfaces have too much pitting? Didn't look like it last time I had it all apart but I still use the original cast iron intake and 'stat aluminum housing.
What is optimum gray? The permatex ultra grey/black sealers work very well to stop any type of seeping or leaks in coolant or oil applications. If its spread thin over the whole gasket surface & not just a small bead and allowed to fully cure, it literally seals the gasket & should stop any leaks or seepage. Unless there is major pitting that the sealer isnt filling, but even then on pitted timing covers if you fill the pits with the sealer it has always been leak free in my experiences.

  #10  
Old 04-02-2024, 12:45 PM
dataway's Avatar
dataway dataway is offline
Ultimate Warrior
 
Join Date: Jan 2012
Location: Saratoga NY
Posts: 8,942
Default

Helps to use a sanding block on the intake and lap the housing on something flat. If both surfaces are flat and smooth you get a good squeeze on the gasket. And of course don't over tighten the housing, the ears will bend and it will always seep.

__________________
I'm World's Best Hyperbolist !!
  #11  
Old 04-02-2024, 05:53 PM
grandam1979 grandam1979 is offline
Ultimate Warrior
 
Join Date: Feb 2005
Location: Ohio, Findlay
Posts: 1,437
Default

I just bought a batch of the thin blue Felpro gaskets have a few of the black ones left you get from the usual Pontiac shops they are like a sponge.

  #12  
Old 04-04-2024, 08:35 PM
JEC3039 JEC3039 is offline
Member
 
Join Date: Jan 2016
Location: South Lyon, MI
Posts: 43
Default

Thanks for all the replies.

I'm going to finish the two builds I'm working on with just RTV, no t'stat housing gaskets this time, and I'll see how that does. I'm a sucker for good advertising so I'll try the Permatex 22071 pump & stat RTV.

Thanks again all.

  #13  
Old 04-05-2024, 08:22 AM
nUcLeArEnVoY's Avatar
nUcLeArEnVoY nUcLeArEnVoY is offline
Senior Member
 
Join Date: Sep 2021
Location: Homestead, FL
Posts: 183
Default

Quote:
Originally Posted by JEC3039 View Post
Thanks for all the replies.

I'm going to finish the two builds I'm working on with just RTV, no t'stat housing gaskets this time, and I'll see how that does. I'm a sucker for good advertising so I'll try the Permatex 22071 pump & stat RTV.

Thanks again all.
Yep, like I said that's how the service manual usually recommends doing it. A 1/8" bead on the gasket surface to resemble an O-Ring usually works just fine, just make sure to only hand tighten down the the bolts and let the RTV cure for an hour before torquing to spec.

__________________
1979 Trans Am W72 400/4-Speed WS6 - Starlight Black Hardtop
  #14  
Old 04-06-2024, 03:18 PM
mchell's Avatar
mchell mchell is offline
Ultimate Warrior
 
Join Date: Jul 2003
Location: North Port, FL
Posts: 2,557
Default

I use these teflon gaskets on my intake crossover and water neck housing…works like a charm

https://tinindianperformance.com/Pon...%20Gaskets.htm

__________________
71 GTO, 463, KRE 295 cfm heads ported by SD Performance, RPM intake, Qjet, Dougs Headers, Comp cams HR 246/252 ...11 to 1 , 3.55 cogs, 3985lbs.....day three- 11.04 at 120mph ....1.53 60', 6.98 1/8 mile
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 08:53 PM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017