Thermostat Housing Seal Problem:

[Daniel K.]

[John H.]

Re: Thermostat Housing Seal Problem:

Dan -

GM now has a fiber thermostat housing gasket with a circular silicone rib molded on each side (GM #10105135); seals perfectly, looks just like the originals when installed, and isn't like that ugly blue thick thing that Fel-Pro sells.

[Daniel K.]

Re: Thermostat Housing Seal Problem:

Thank you John. I will order/pick one up tomorrow. Appreciate your help! Dan K.

[Charles P.]

Re: Thermostat Housing Seal Problem:

Would that part number work for other applications, say a 72 small block?

[Joe R.]

Re: Thermostat Housing Seal Problem:

Hi Dan:

I had the exact same problem with a "peel and stick" thermostat gasket that I got from Paragon.

I think the adhesive applied to the gasket is not automotive grade, and it deteriorates when it gets hot. Even if you apply another sealant, the adhesive that comes on the gasket may prevent the sealant from sticking to the gasket. The "peel and stick" gasket is also a little thin.

I solved the problem by getting a standard fiber gasket from, I think, Long Island Corvette. This gasket is thicker and has no adhesive on it. I used Permatex Ultra Copper RTV as a sealant, and there have been no leaks.

[Wayne P.]

Re: Thermostat Housing Seal Problem:

Before you install the new gasket make sure the housing is flat. Many times they are warped. You can cure this by taping a piece of sandpaper to a flat surface and rubbing the housing mating surface on it until flat.

[Pierre J.]

Re: Thermostat Housing Seal Problem:

Had the same problem with my '56. At the recommendation of this board I installed an expensive "Fel-Pro 2202" gasket. Haven't had a problem since.

Pierre
34410

[John D.]

Re: Thermostat Housing Seal Problem:

Dan, I have another theory about your problem. Your set up is the same as the FI cars. Aluminum intake and aluminum outlet. Here is how I use the readily available- inexpensive gasket that I buy from Carquest.
I take the top water outlet over to my surface plate and sand it flat. I mean those things are warped big time. I use various grades of emery cloth or sand paper to get them 100% flat. Just did one yesterday for a 62 and my arm was sore. Then I use a straight edge on the base plate or intake and file it flat.
Then when I put on the gasket I don't have any leaks.
I don't use any forma a gasket stuff either as the judges hate it. By the way you have to be careful with that stuff. It comes in three grades. #1, #2, #3.
I like the #3 which is for aviation use. I leave the cap off the jar until it gets like molasses. Then apply it with a q-tip. But I don't use it for uneven surfaces. That's a crutch and it won't work as you know. Good luck, John

[Joe L.]

Re: Thermostat Housing Seal Problem:

Charles-------

It's the same for all 1955 to 1991 Corvette V-8's.