One side of the screw is coated. To me it looks like sand can embed in it and make it a grinder on the other screw. There is all kinds of pastey metal goo all over it. I think some of the lube was getting through the bearings. Time for the spare! This SC has close to 90K on it.

The phenolics I just ran into over the years here, the SC spacer is from 240M3, the lowers are TVT and the uppers are LET.

I tried the 180 stat over the winter and it seemed like the CEL was pending and did not cause illumination.