Used Pennzoil Supreme Duty 15-40 since the truck was new, until the last 4 oil changes where I switched to Pennzoil Long life. Ever since going to the Long Life, I have an oil/vapor aroma when the truck is idling, gets less with mileage on the oil, but always there. Even tried Rotella T on the last change, and after 60 miles it still has that oil/vapor aroma. What is up? Should I go to the dealer before the expires for rings? Or just go back to the Supreme Duty? I have heard of the 24 valvers doing this? But I don't think my truck added some valves between oil changes.