I agree with you, Ali. I've been looking for Mobil 1 0-40 unsuccessfully. I have been using Mobil 1 5-30 in winter, 15-50 in summer, but until the 0-40 is available will probably stick with the 15-50 all year long in the future. I've heard from a number of folks who live in colder parts of NA than Omaha who say 15-50 works great in winter. (Specs say it's pourable until -54 degrees F or so.)

My idle oil pressure went from 0.5 to 1.5 in summer when I made the switch to synthetic.

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Steve
'93 400E