From what I have gathered here, the only reason many car manufacturers are switching to 5W/20 motor oil is to boost CAFE numbers. This may help an auto manufacturer look good over the whole spectrum of autos that they sell. For the consumer, however,the use of 5W/20 only boosts fuel economy a few tenths of a mile per gallon. There may be nothing "wrong" with 5W/20 motor oil, but if the benefits are so miniscule, why use it and take the chance of compromising protection? I have switched to using 5W/30 in my Grand Caravan due to a consumption issue that I am trying to resolve. I will probably stick with 5W/30. Has anyone else switched to 5W/30 in a vehicle spec'd for 5W/20?