Coolant Reservoir Fills, Doesn’t Empty / VSS Issue

[SAL]

— I had a new Stant cap, but thinking like you… I switched to the OEM with yellow Japanese sticker. I may just have to do a combustion gas test.
— On the VSS, I have factory size 195/70-14 Hankooks with 7500 miles on them. The original VSS has 22 teeth on the gear. Same as the new one. Maybe I got a dud new one out of the box. I’m stumped. THX.