I have a 2000 Dodge Grand Caravan Sport that's not quite ready for replacement and we are planning a July trip to San Antonio, where it's obviously going to be very hot. It's the 3.3l FF and has been serviced most of it's life at a local service center every 3-5,000 miles with whatever bulk dino they use. It's got 160,000 miles on the clock. I'm thinking about putting in Pennzoil High Mileage 10W-30 before the trip. This is a change from it's normal (and recommended) 5W-30 but I figured the reduced viscosity additive might help just a little in the extreme heat. What do you think of this choice and do these "boutique" oils really do anything for you--after all, it's done just fine on bulk dino and a fresh private label (cheap) filter all these years.