Installing thermostat & goose neck
Melting Slicks
Joined: Oct 2006
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From: hebron IL
C3 of Year Finalist (appearance mods) 2019
I know some of the new goosenecks come with an o-ring which requires no sealant. If you are using stock with a gasket I would use a little blue RTV
Thread Starter
Melting Slicks
Joined: Jun 2016
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From: Woodinville WA
Safety Car
Joined: Nov 2005
Posts: 3,532
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From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Is this a stock GM type neck with the a slightly raised bump all around in the center of the neck flange? If so, you do not need any sealant at all using a Felpro paper gasket. Make sure its clean and dry and just bolt it down, torque to spec, it shouldn't leak. 
Also, it doesn't matter which side faces up, blue or striped. If it does matter, Flepro always puts it on the gasket which side faces up.
Also, it doesn't matter which side faces up, blue or striped. If it does matter, Flepro always puts it on the gasket which side faces up.
Last edited by Buccaneer; Mar 13, 2018 at 01:51 AM.
Melting Slicks
Joined: Oct 2000
Posts: 2,142
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From: Englewood FL
I would recommend putting some anti seize on the bolts. I had a 1979 which has an aluminum intake and the bolts seized to the aluminum. Next time I changed the thermostat one bolt snapped. The bolt holes are blind holes, so no danger of fluid weeping from the manifold.
Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
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From: Woodinville WA
Thanks everyone; I had to go with an adjustable gooseneck to ensure it would clear all the throttle assembly bits so just assembled it a few weeks back to make sure everything would clear. It’s actually an oring design so I guess I’m good as-is except for adding some anti seize to the bolts.
Adam
Adam
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Thread Starter
Melting Slicks
Joined: Jun 2016
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From: Woodinville WA
Adam
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
This is what better engineered c-3 vettes use. It makes it so you can completely fill the radiator system?
https://www.summitracing.com/parts/mor-63420/overview/
https://www.summitracing.com/parts/mor-63420/overview/
Safety Car
Joined: Nov 2005
Posts: 3,532
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From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Also...Using no sealant on Felpro paper gaskets is also true for the water pump contrary to popular belief. The plain paper gasket will work just fine and not leak. Clean and dry, that's it.
Last edited by Buccaneer; Mar 13, 2018 at 02:23 PM.
Race Director
Joined: Apr 2011
Posts: 11,183
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From: North of Toronto - Ontario
Also check the mating surface of the intake. If it's an old aluminum intake they are sometimes pitted and the O-ring may/will not seal properly and then you'll have to make a bunch of posts on how O-ring housings are crap and that you'll never buy another one.
Or, if it is pitted, simply put some right-stuff (or sealer of your choice) on and then a paper gasket and your o-ring gasket on top of that (with no sealer)
Some even remove the o-ring and use just the gasket, I'd leave it, easier to remove later if need be
M
Or, if it is pitted, simply put some right-stuff (or sealer of your choice) on and then a paper gasket and your o-ring gasket on top of that (with no sealer)
Some even remove the o-ring and use just the gasket, I'd leave it, easier to remove later if need be
M
Racer
Joined: Feb 2012
Posts: 421
Likes: 27
From: Harrisburg PA
I never had an o ring seal properly...even on brand new to brand new surfaces. just unlucky, I guess!!
I always use a felpro gasket, and always put a thin coat of RTV on each side of the gasket. perhaps a bit overkill, but never a leak!
I always use a felpro gasket, and always put a thin coat of RTV on each side of the gasket. perhaps a bit overkill, but never a leak!
Team Owner
Joined: Jan 2006
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From: Crossville TN
No sealant on the T-stat. Sealant on the gasket(s), if needed. I much prefer Permatex Gasket Sealer to any kind of silicone sealant. The only time I will use a silicone based sealant is on oil pan or valley cover corners; and then Permatex Ultra Black RTV is the sealant of choice.
Race Director
Joined: Apr 2007
Posts: 11,150
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From: South Western Ontario
Was it a housing similar to an Edelbrock 4818 or a o-ring type seal around the outside of the thermostat?
I had one like the 4818 and used it on and off a bunch. Got rid of my last small block that could use it so Dad now has it on his 78. Have not changed the o-ring yet and no leaks yet.
Safety Car
Joined: Nov 2005
Posts: 3,532
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From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
I know there are plenty of people out there that think you need to seal the cooling system gaskets with sealant, but that is old school thinking for sure and I'm not trying to be condescending here.
If the surfaces are in good shape, flat, dry and clean, there is no reason you need to use sealant on water neck or water pump gaskets. Felpro, if used, was designed to be used without sealant even though they are paper.
Go here at the manufactures site and do your research on the subject, ask questions if needed. If you are leaking, check your bolts.
http://www.felpro.com/professional-forum.html
If the surfaces are in good shape, flat, dry and clean, there is no reason you need to use sealant on water neck or water pump gaskets. Felpro, if used, was designed to be used without sealant even though they are paper.
Go here at the manufactures site and do your research on the subject, ask questions if needed. If you are leaking, check your bolts.
http://www.felpro.com/professional-forum.html
Last edited by Buccaneer; Mar 15, 2018 at 04:18 PM.
Racer
Joined: Feb 2012
Posts: 421
Likes: 27
From: Harrisburg PA
Was it a housing similar to an Edelbrock 4818 or a o-ring type seal around the outside of the thermostat?
I had one like the 4818 and used it on and off a bunch. Got rid of my last small block that could use it so Dad now has it on his 78. Have not changed the o-ring yet and no leaks yet.
I had one like the 4818 and used it on and off a bunch. Got rid of my last small block that could use it so Dad now has it on his 78. Have not changed the o-ring yet and no leaks yet.
Dr. Detroit
Joined: Mar 2012
Posts: 10,093
Likes: 4,017
From: New Braunfels Texas
If the aluminum is in good shape on the intake.....then no sealant is needed if it is FLAT.
Take the water neck and put a piece of 80 grit on a flat plate or granite stone to check and make the surface flat. Do this to the intake also if it is off the engine of course.
And that is exactly what I did with my OEM GM neck......I also heli-coiled the intake and used ARP bolts......I'll never have a problem.
Jebby
Take the water neck and put a piece of 80 grit on a flat plate or granite stone to check and make the surface flat. Do this to the intake also if it is off the engine of course.
And that is exactly what I did with my OEM GM neck......I also heli-coiled the intake and used ARP bolts......I'll never have a problem.
Jebby
Burning Brakes
Joined: Jan 2006
Posts: 1,071
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From: Clear Lake Shores Texas
2016 C3 of Year Finalist
I finally fixed the leaking thermostat housing on my 72 LT-1 by using a GM gasket # 10105135 which has a silicon ring built into it. My local Chevy dealer had them in stock.