Okay, I doing an oil change for the parents on their Focus. The oil filler cap says use 5W20 which has generally been what I've put in the car in the past. However looking at the emissions sticker on the hood it says 5W30. The Owners manual is long gone and the Ford dealer says use 5W20. It has the 2.0L Zetec engine and 170,000 miles and runs great. Is 5W20 really okay for this car in the summer heat? Reading on the Ford Focus forums it seems that the spec was changed for the 2001 model year.