bogus wrote:
the larger bearing in the gen 2 opti helped a lot with lifespan.

The Mitsubishi sourced optical sensor is killer durable... 300k or more. A friend worked at a Dodge dealer and saw a lot of them come through in Mitsu engines, and with tons of miles on them, still going strong.

A simple fix for the Gen 1 is to pickle the cap to opti chassis with copper RTV, then, using some line and fittings, a coolant drain bypass will work wonders.