im about to change my oil and i noticed my dad bought 0-30W mobile1 instead of the usual 5-30W. will it be ok if i use the 0-30W? and i have 4qts of the 0-30 and i have 1quart of 5-30, would it be ok if i mixed them? thanks in advance

 

Your call.
I wouldn't do it, unless you live in Alaska.

Here's a breakdown of what the Viscosity #'s mean:
[X]W-[Y]
[0]W-[30]
[5]W-[30]
[10]W-[30]

X is the oils lowest viscosity, this is at low temperatures.
Y is the oils viscosity at operating temperatures [higher temps].

Oil is thinner at sub-operating temps so that it coats the internals quickly. As temps rise the viscosity rises to create a "barrier" or "film" of oil between moving parts which is more resiliant to breaching.

Because 0W-30 has a larger spectrum of viscosity, itwill take longer for the viscosity to reach 30 after starting the engine. This could prevent your engine from having that vital "film" between the hot moving parts when it needs it most. [At least until the viscosity reaches 30]

5W-30 only, unless you are like me, living in TX using 10W-30 during the summer. Although I contemplate a switch to 5w-30 permanently.

Hot Rod Magazine has a "Synthetic VS Non-Synthetic Oil" article in this month's issue (August), might want to swing by the magazine rack and check it out. I really appreciate that magazine.

Good Day.

 

I forgot your other question, sorry.

Mixing oil viscosities is not detrimental.

 

If Honda recomends 5w30 I think I would go with what they say.