WhoDey456 wrote:Ken in AZ, I believe he said he uses 0w-40? Not sure...
I use Mobil 1 0W-40 regularly ... even though I am not in sub-zero weather. This is an excellent oil and highly recommended by an oil expert I know - which is why I use it instead of "regular" 5W-30.
Of course, 0W-30 will be fine for winter months in Iowa. BTW, the manual does tell you that 5W-30 will work to pretty low temperatures as well.
To the OP: you should get 6 quarts (six 1 qt bottles, or one 5 qt plus an extra 1 qt) of oil for a change, since the M45 takes 5 7/8 quarts with a filter change (and you do that at the same time too, right? Right?? )
Z