Originally posted by Rara:
Unfortunately it isn't data I can post or do anything more than allude to, because it was Ford internal testing for proving out the use of the 5w20 oil. As far as I know, all the testing still passed Ford's wear requirements, but that it wasn't as good as the 5w30. Some of you seem to think that 5w20 will instantly blow up your engine or something, it won't it will work fine. The difference you would see, is if you took two identical engines, run them exactly the same for 100,000 miles, and then tear them down, and you will see more significant wear on the engine that has run the 5w20. It will be especially noticable for engines run in hot climates.

The real truth is just that it was done for fuel economy reasons and nothing else. It netted something like an overall 0.5mpg improvement in Ford's CAFE numbers, which meant big bucks for the struggling automaker.



I was just curious, I ran the 5w20 in my Lightning and didn't see any change or bad wearing with the oil. Hell, last oil sample it was the 'best' 5.4 they had seen that month. I knew it was only for the CAFE numbers, but figured they would have published them if it noted a change in oil viscosity.

Ryan Trollin!