I have a 2005 Honda Odyssey. About two months ago I change the oil with Pennzoil platinum 5W 20. Recently I've noticed tiny little spots of oil barely larger than a pin head on the floor. I always wipe them up and within a couple of weeks there are a few more again. I can't seem to find any leak around the filter or the drain plug. Vehicle has 120,000 miles on it. I always used regular Valvoline conventional before. This is its first time on synthetic. i'm wondering if I need to switch to a high mileage oil? After two months I thought any residual oil that may have gotten on the frame and the dripping off would be gone by now? any advice?