I use Mobil Delvac 15W-40 in both my old cars. 5 weight is too thin IMHO. A lot of folks like 10W-30 and have good luck with it but I feel it's still a tad too thin. Any 15W-40 that meets current spec will do just fine. You don't need to pay the Rotella price. The Delvac is 50-60% the price of Rotella.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.