Thermostat Gasket

[Pierre J.]

A while back I bought, from a GM dealer, a thermostat gasket that had a bead of silicone on both sides around the opening. I somehow misplaced the part number and I am looking at purchasing this gasket again. Would anyone have the part number for this gasket?
Thanks,
Pierre

[John H.]

Re: Thermostat Gasket

Pierre -

It's #10105135. Great gasket, can't be told from the original when installed, won't leak.

[Pierre J.]

Re: Thermostat Gasket

Pierre -

It's #10105135. Great gasket, can't be told from the original when installed, won't leak.

Thanks John, much appreciated.

Pierre

[Patrick H.]

Re: Thermostat Gasket

I gotta believe that someone else makes the gasket and it can be purchased for less somewhere other than the usual greedy GM parts man?

Or is it a GM-only item?

Patrick

[Dale S.]

Re: Thermostat Gasket

Fel pro used to make one like that. Not sure it was exactly the same. Dale

[John D.]

Re: Thermostat Gasket

A job I don't like but do anyhow is to lap the thermostat housings flat as they are typically warped, etc.
Use a granite surface plate and various grades of sandpaper till your arm gets sore. Do NOT use a belt sander.
Then you can go to your local Car Quest store and buy a really nice original looking gasket cheap. C25930. I buy them in packs of 10 and use them exclusively on all FI jobs. Never had a thermostat area leak. Gasket is sticky on one side.
Not fun sanding cast iron 'stat covers but a necessary evil. Just installed an original 'stat cover on a 63 Fi and couldn't believe how bad it was eaten and warped.

[Clem Z.]

Re: Thermostat Gasket

A job I don't like but do anyhow is to lap the thermostat housings flat as they are typically warped, etc.
Use a granite surface plate and various grades of sandpaper till your arm gets sore. Do NOT use a belt sander.
Then you can go to your local Car Quest store and buy a really nice original looking gasket cheap. C25930. I buy them in packs of 10 and use them exclusively on all FI jobs. Never had a thermostat area leak. Gasket is sticky on one side.
Not fun sanding cast iron 'stat covers but a necessary evil. Just installed an original 'stat cover on a 63 Fi and couldn't believe how bad it was eaten and warped.

if they are realy bad why don't you have a machine shop fly cut them flat ?

[John H.]

Re: Thermostat Gasket

Fel pro used to make one like that. Not sure it was exactly the same. Dale

Fel-Pro still makes them, but they're blue molded plastic about 1/8" thick and look ugly when installed. The GM gasket is brownish thick paper with a circular silicone bead seal molded on both sides, and looks perfectly ordinary when installed. They come in packs of ten.

[Steven B.]

Re: Thermostat Gasket

Do the GM gaskets look correct for all years (especially '57, '77, 78)?

'Remember when the gasket was free with a thermostat? My parts guy, and neighbor, used to give me 2 or 3 when I got a new thermostat.

Steve

[John H.]

Re: Thermostat Gasket

Do the GM gaskets look correct for all years (especially '57, '77, 78)?Steve

As far as I know, yes - they've used that same gasket pattern for decades.

[Steven B.]

Re: Thermostat Gasket

Thanks John! 'Always appreciated.

Steve