Originally Posted by Scrambler82
Use what FORD calls out !
I run the 5-20 all the time here in the north east, when I get to SoCal I will check around for what oil is called for out there, thinking the same stuff but maybe a little heavier.
I'm a big OEM guy but not when it comes to oil.
5W-20 is spec'd in order to meet MPG requirements set forth by the Fed Gov't. Also, it's much cheaper than a full synthetic motor oil of Group IV. If you do a lot of driving in the South, a 0W-40 will offer far greater protection in high heat situations and at least, with Mobil 1 0w-40, be thinner on cold startups than Ford's 5W-20.
So you WILL have much greater engine protection from the Mobil 1 product but you might lose a tiny bit of MPG's, although the opposite could very well be true since it is a fully engineered product that has same shaped molecules vs Ford's C III mineral oil based product.
All in all, it is far superior protection and costs less than $5 a quart.