question about oil & sending sample to lab for analysis

[rexcramer]

One man's opinion; use the 0/40, especially for your cold area. In the really hot S/W (over 100) you could use 5/40. All the under-drive pulley does is slow down the aux rotational speed of the water pump, alternator and the A/C compressor. The idea being that it frees up some HP and lengthens the life of the aux. This really helps if you are always pedaling at or near red-line all of the time. And same oil either way. I would run the oil sample to get a base line. Your report will measure the solids which is what you are most worried about. Put a note in with the sample and tell them how old it is.