Anyone know if you can use a FelPro 35485 gasket to seal the thermostat in a "C" 3800 ? The original GM part seems to be unobtainable. This goes on the thermostat itself and is not the O'ring (FelPro 00427).

And what is a 12337901 ? ACDelco says to use it in place of both the O'ring and the gasket.

Are you talking about the rubber piece that mates up with the tstat and the tstat housing? I don't know about needing one. I don't have one [but I have the o-ring that the tstat housing and intake mate up with]. I haven't encountered any leaks. Is your'* damaged or missing? Best bet is to take your'* along when purchasing one. Mine was in flawless condition. I know it may sound dumb, but you could probably get one in the junkyard that may be in good condition.


-justin

More of a perrenial issue that I am trying to nail down, what are the actual part numbers ?. In Orlando I do not have a problem with not enough heat but there was a TSB on the issue and that is when the second gasket was added.

Do you have the text or the general idea of the TSB? Sorry for the off topic.
I replaced the thermostat once in my 88 Royale and could NEVER get decent heat from it unless I put cardboard over the radiator in the wintertime.

I recently changed the t-stat in MrsCrzydmnd'* to a 180 and she complains of not enough heat lately too, bad enough that she drives mine instead. I also used only one gasket. I have the Fel-Pro O ring new in the package in the shop, can post it tomorrow and maybe see if its different from yours?

Hmm.. you have me curious now, because I never used the heat after my tstat replacement. I think I need to find that gasket. If I can, do you want a pic of it? Or do you know what to look for?


-justin

Haven't seen the new gasket so a .jpg would be useful. Is a picture on the AC Delco page but just looks like an O'ring. May put together a web page on the subject, it keeps coming up.

"could never het enough heat out of my 91... It'll get warm but thats it"

Have seen two things do that. The first is a stuck open thermostat so the coolant never gets warm enough. The second is a stuck hot-cold diverter (most common with ATC - is behind the glove compartment) the coolant reaches normal operating temp (anything over 150F) but the heater doesn't do much. With the second often the A/C is not up to snuff either.

the only thing listed is a O-ring and Seal outlet gasket isnt available
Felpro seal PN 35126
Felpro o-ring 35608

Might be because there is no gasket on a "C" engine - water seal is with the O'ring and the "seal" may be the part to keep coolant from bypassing the thermostat (goes between the water neck and the thermostat).

I have one. I guess I am just special .


-justin