These are good facts that you mention ski-dood.I aggree the bearing did overheat I don't think anybody disagrees. Overheating causes bearing wear and failure. The wear on the balls and the inner race is definetly from heat. But I don't think it comes from the lack of coolent contact or coolent efficiency.
When the balls become worn like the ones in this picture, it creates an increase in surface friction. This heat from friction has a much bigger impact than improper cooling. And is degenerative, which means that the more you run, the more heat is created, which means the more wear is created, which means the more heat is created and so on, and so on.
This wear is what I think cause the crank failure. Because eventually the looseness caused flexing in the crank.
Thats another good point on the outer race being compressed. This causes the balls the run harder/hotter and fail. But I don't believe that this type of application can cause this. You sound like your familiar on this type of failure probably because you work on split bearing cartridges that need to be shimmed, or on the taper roller bearings that you need to tighten up the locknut on the taper sleeve in order to achieve proper clearences. And we all know what happens when they are improperly installed. You run the equipment up to speed, measure the temp, and watch as the temp keeps climbing to critical.
But on the type of bases on sleds, I don't think it would be possible to compress the race enough. The only way I could see this happen is if the groove where the bearing sits in the housing was damaged and had a high spot or not properly cleaned. Then I could aggree that this could cause the bearing wear.
Using locktite only creates a film, the excess gets pushed out plus I don't think it has the strengh to compress the race.
As far as the locktite goes for heat transfer, it does not have the "R" value to insulate. So basically if the bearing is hot, the locktite is hot, so heat will still be removed.
Interesting theories, but in the end, we both may be wrong. These are just our 2 cents and don't actually have the bearing in front of us to study.
Just my opinion