Dear jd620,

Hope you're well. I've stood aside, to let others more qualified reply. I had thought that Viton seals were grey, while silicone seals were red-orange. I cannot be sure that was always so, much less that if it was so, that it still is so. .

Thus, to be sure of getting a top-quality seal, buy the Volvo brand item. These have long track records of durability. Given the amount of work needed to remove/replace a crank seal, the "extra" cost of getting the Volvo-brand item seems reasonable.

Hope this helps.

Yours faithfully,

Spook