Late-style SB thermostat housing...those dimples

[TylerW]

Hey guys:

Before I decide that I'm smarter than the Chrysler engineers that designed them and take measures to mitigate them, why is there a dimple on each end of the later style "tin" thermostat housing? I had to replace the original on one of my engines and it had them. The replacement also had them and it does not sit anywhere near flush.

The intake manifold mounting surface is completely flat and logic tells me that the mating surface of the thermostat housing, ideally, should also be flat. Thanks for any insight.

 

[AJ/FormS]

Leave 'em on there.
I wanted to grind them off too, but I got to thinking about it and this is what I came up with;
Look where they are, outboard of the mounting holes right?Take a look at the sealing ring ....see how it thins out as it comes around to the bolt-holes?
My thought was that when you bolt the housing on, the nipples preload the flange and make it act like a spring,and this forced the sealing ring ever tighter onto the gasket.
In any case the nipples pass thru the gasket elongated mounting holes, and sit tight on the manifold metal. In no way can the cause a leak; so I left them alone, cuz I also thought those engineers were probably smarter than me.

 

[TylerW]

Well, what actually went down was that I installed this thing as-is, with sealer against the intake, then a new gasket, then the thermostat, then the housing. And, it leaked. Not while running, but each night when it cooled down it leaked. So, I took it off, ground the dimples, sealer on both sides of the gasket, reinstalled, dry as a bone. Live and learn.

 

[Lelo Dart]

Well, what actually went down was that I installed this thing as-is, it leaked.

Me too. Installed twice, still leaked. Went with the tall magnum water neck.