Few ?'s oil change etc....

[X5DINAN]

Hey guys I have a couple of questions,
-I want to do an oil change this weekend on my 2002 4.4l (180,000 km). Should I use 0W40 Mobil1 (what I use in my AMG) or
should I use 5W30 Syn. Castrol?

-On cold start ups, my truck makes a crazy airplane sound coming from the secondary pump. The noise goes away
in about a minute and a half. Should I be concerned about this now, and just deal with it in the Spring? Can I disconnect it?

-Also I have a coolant leak (puddle) the next day after my truck has been sitting over night? I think it's coming from the top
hose off the expansion tank (plastic fitting)? Is this common or should I be looking at other culprits?

Thanks All