BB Thermostat Housing gasket tricks

[JRSully]

Tried twice replacing the thermostat housing gasket on my L78 and twice it is leaking. Any tips.? What gaskets work the best.? It's not August, I need the 'stat. Thanks

[Mr70]

Sounds like one of the machined surfaces is irregular,be it on the intake or thermostat housing.I've found over time they can get minute craters due to deposits forming,or the aluminum as well could be warped on either.
Have you looked real close at both with a straight edge?

[Chevy454]

The blue Fel-Pro gasket is the best, it will seal about anything...the correct fix would be to fix the housing, but if you don't mind seeing just a bit of blue peaking out the gasket is the easy fix.

[m22mike]

[ QUOTE ]
The blue Fel-Pro gasket is the best, it will seal about anything...the correct fix would be to fix the housing, but if you don't mind seeing just a bit of blue peaking out the gasket is the easy fix.

[/ QUOTE ]

When I use the blue Fel Pro's I go around the edge with a black marker before installation, then you will not see the blue
And I likes Indian Head gasket sealer


Mike

[Postsedan]

Use a flat belt grinder with a non aggressive sand paper...then use a GM gasket with a built in 0-ring, available at any GM dealer.

Dan.

[169indy]

I agree the FELPRO thermo gasket works GREAT!
From Felpro:
Seepage around a thermostat is common because typical paper thermostat gaskets cannot conform adequately to the warpage and corrosion of the housing flange. A thermostat leak will be obvious to the vehicle owner.

Fel-Pro® offers a complete line of replacement thermostat gaskets for most makes and models of light-duty vehicles. Fel-Pro also offers PermaDryPlus thermostat gaskets for problem-solving applications.

These PermaDryPlus gaskets feature a rigid-carrier construction and silicone sealing beads. The carrier prevents overtorquing and ensures instant fit and perfect alignment. The molded rubber assures a secure seal, helps eliminate leak paths and is highly resistant to extreme temperatures. These gaskets are the perfect solution for warped or corroded thermostat housing flanges found in the repair market.

http://www.federal-mogul.com/en/Aftermar...emostatGaskets/

Part Number for SBC in 1996 was: MIS2002

Mine has sealed for years with NO signs of failure,,the Mr. Gasket paper gasket on my BB always has a strange mung that develops around the housing.

Jim

[JRSully]

Thanks all, going with the Felpro Perma Dry, stay tuned. Tired of draining the rad to fix this. All else fails I have a NOS 660 housing in the box.

[JohnZ]

The GM gasket with silicone ribs molded on both sides is P/N 10105135; seals just like the Fel-Pro, but without the ugly thick blue appearance. No indication that it's anything but the original when installed.