My guess is if the viton purple seals were used, there are variations between aftermarket and OE. The OE seals will fit and hold in the cooler channels, the aftermarket ones are hit or miss. Possibly used RTV to hold them in place on the cooler for installation. Also used too much.

When I did mine, I did apply a layer of Hylomar to both sides of the seals. This provides the holding power to keep them in place when reinstalling and also allows the seal to adjust to mating surfaces when tightening, also it never fully hardens and appropriate for this type of use. If you don't have any, the seals should go in dry.

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