Question about thermostat housing - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**NGN** · 07-19-2023, 07:04 PM

How perfectly flat should the surface be and how much pitting is too much pitting. From what I can read off the numbers,
GM • 3877660 . Any venders on here with new replacement?
Also is it possible to mill down some, just a thought.
Ill never forget what my high school cooking teacher said back in the days, when in doubt throw it out lol.
Thanks
NGN
Nick

**Steeveedee** · 07-19-2023, 07:52 PM

If you have a piece of wet-or-dry sandpaper, you can dress it back to no pits. Alternatively, you can use #1 Permatex to seal it. Just know that it'll be tough to get off later. I had a '75 Dodge that I put a timing set in way back when. No new timing cover gasket, just that #1 Permatex. Didn't leak a bit.

weq92f · 07-19-2023, 07:58 PM

.

I have installed/R&R very nasty looking housings in the past using both gasket and silicone. None leaked. They don't like to come apart afterwards though.

My current setup uses an oring type seal that I could not get to seal...always leaking/weeping. I removed the oring and used regular gasket with success...go figure.

-klb

**truckster** · 07-19-2023, 08:12 PM

Sandpaper (face-up) on a flat surface. Round and round and back and forth. Good as new.

**MySons68C20** · 07-19-2023, 11:18 PM

Quote:

Originally Posted by truckster

Sandpaper (face-up) on a flat surface. Round and round and back and forth. Good as new.

This works!

72c20customcamper · 07-20-2023, 09:33 AM

If you want to keep the original I have filled pits in housings on my Studebakers with JB Weld . Clean the housing well with brake clean or lacquer thinner fill and sand with fine paper as mentioned prior . This way just a coat of Indian head gasket shellac and your good to go

**dmjlambert** · 07-19-2023, 09:40 PM

If after that yours doesn't turn out good as new, or to answer your question about vendors here, I bought one of these from specialtyretail http://67-72chevytrucks.com/vboard/s...d.php?t=838785

**Warrens69GMC** · 07-19-2023, 09:46 PM

Dorman 902-2014, you need 1 longer bolt.

https://www.amazon.com/Dorman-902-20.../dp/B01CS3K4N4

**Ironangel** · 07-19-2023, 10:47 PM

Quote:

Originally Posted by Warrens69GMC

Dorman 902-2014, you need 1 longer bolt.

https://www.amazon.com/Dorman-902-20.../dp/B01CS3K4N4

What Warrens69GMC said! Save the sand paper for the manifold. Like said, silicone both sides of the gasket, tighten evenly...

07-19-2023, 07:52 PM	#2
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,676	Re: Question about thermostat housing If you have a piece of wet-or-dry sandpaper, you can dress it back to no pits. Alternatively, you can use #1 Permatex to seal it. Just know that it'll be tough to get off later. I had a '75 Dodge that I put a timing set in way back when. No new timing cover gasket, just that #1 Permatex. Didn't leak a bit. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

07-19-2023, 07:58 PM	#3
weq92f Registered User Join Date: Oct 2016 Location: Dallas Texas Posts: 3,218	Re: Question about thermostat housing . I have installed/R&R very nasty looking housings in the past using both gasket and silicone. None leaked. They don't like to come apart afterwards though. My current setup uses an oring type seal that I could not get to seal...always leaking/weeping. I removed the oring and used regular gasket with success...go figure. -klb __________________ 67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold

07-19-2023, 08:12 PM	#4
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,976	Re: Question about thermostat housing Sandpaper (face-up) on a flat surface. Round and round and back and forth. Good as new. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

07-20-2023, 09:33 AM	#6
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,716	Re: Question about thermostat housing If you want to keep the original I have filled pits in housings on my Studebakers with JB Weld . Clean the housing well with brake clean or lacquer thinner fill and sand with fine paper as mentioned prior . This way just a coat of Indian head gasket shellac and your good to go __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

07-19-2023, 09:40 PM	#7
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,859	Re: Question about thermostat housing If after that yours doesn't turn out good as new, or to answer your question about vendors here, I bought one of these from specialtyretail http://67-72chevytrucks.com/vboard/s...d.php?t=838785

07-19-2023, 07:04 PM	#1
NGN Registered User Join Date: Nov 2001 Location: Old Bridge,NJ Posts: 838	Question about thermostat housing How perfectly flat should the surface be and how much pitting is too much pitting. From what I can read off the numbers, GM • 3877660 . Any venders on here with new replacement? Also is it possible to mill down some, just a thought. Ill never forget what my high school cooking teacher said back in the days, when in doubt throw it out lol. Thanks NGN Nick

07-19-2023, 09:46 PM	#8
Warrens69GMC Registered User Join Date: Jan 2003 Location: Safford,AZ Posts: 3,621	Re: Question about thermostat housing Dorman 902-2014, you need 1 longer bolt. https://www.amazon.com/Dorman-902-20.../dp/B01CS3K4N4 __________________ 1969 307, t350 1950 Chevy Wagon 1978 Big 10 1967 C10, 250,3-OTT

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