Don't know about engine longevity requirements. But I believe the manufactures are responsible for replacing major emission control components for up to 120,000 miles now. That's up from 80,000 miles. Maybe someone with a 2004 vehicle can confirm this. To me this means that the engine has to run clean for at least 120,000 miles. In order to do that the engine has to be in really good condition and not worn out. So I guess that the new oils are not meant to shorten an engine's life span. It comes back to new engines spec'd for 5W-20 oils seem to produce really good UOA's, if they are used according to the owner's manual recommendations for mileage and type of service. Are they the answer for all engines, NO! In all honesty I use it for my 2002 Ford truck but for my 1996 Contour I still use 5W-30 synthetic. Especially when Ford first started "back" specifying 5W-20 oil for older vehicles the 2.0L Zetec was originally NOT recommended for use of 5W-20. Later on they changed it. Probably when they came out with the SL grade. I'm sticking with 5W-30. I was using Mobil 1 5W-30 and just filled it with Schaeffer's Blend 5W-30. Though I do have to admit that the Mobil 1 has kept the head spotless from what I can see.quote:
Originally posted by Al:
At one time there was a requirement to certify an engine durability of I believe 150K miles. That requirement seems to have been dropped
Al, I remembering reading a document from a Ford higher-up (president?) about their switching to 20weight oils. He referred to 150,000 miles in that article. I don't have the link on hand, but I'll try and find it. At any rate, I don't believe it's a requirement that 150K be achieved only a milestone at best. More than likely, to make the public believe in their choice to move in this direction.quote:
Originally posted by Al:
At one time there was a requirement to certify an engine durability of I believe 150K miles. That requirement seems to have been dropped