mobil 1 0w-20

0w-20 and 5w-20 are very similar at operating temperature. The difference is how they perform at "cold-start." The 0w-20 will flow "better/easier" than the 5w-20 at cold-start (gets pumped up top to the heads slightly quicker), but once the oils reach operating temps, they are essentially the same lubricant.

Additionally, the new 20 weight recommendation was purely for CAFE purposes (read: Corporate Average Fuel Economy). IIRC, there's a PDF doc floating around that describes how Ford was trying to squeeze out slightly better MPG ratings for their engines and a 20 weight oil provided slightly less resistance inside engines compared to a 30 weight (we're talking nickel dime stuff here, but once you total everything up, CAFE can save a car manufacturer millions of dollars).

A 20 weight oil will perform just fine (ask Joe Lynch), as will a 30 weight oil. Anything thicker than a 30 weight (40 or 50 weight) is probably too thick, unless you are exclusively endurance/road racing (where oil can breakdown under the hot temps of a lengthy racing session).


It's more important to keep a watchful eye on the oil level on these engines instead. Whether you choose to run a 20 weight or a 30 weight oil, make sure you don't let your oil get low. It's a good idea to check the oil level when the engine has completely cooled down as well, since it takes some time for the oil to fully drain back down the oil pan on these engines. Serious damage could result if you run the engine hard without the proper amount of oil, that's why it's necessary to keep a close eye on our oil levels!