The owner's manual for my 1997 Ranger 2.3-liter engine calls for 5W30 oil. Some auto parts sites and online posts say the recommendation has changed to 5W20, based on Ford specification WSS M2C930-A. Apparently the specification is not available online and interpretations vary?

Is there any definitive source on this? If I use 5W20, is a synthetic blend any better than conventional?

 

Many prefer synthetic blends over oil based, you usually only change the filter at 3k miles and add a quart of synthetic as it doesn't break down as fast as oil, so higher cost of synthetic is off-set by that
Also synthetic should really only be used if you have NO OIL LEAKS, as it gets expensive to keep "topping it up", lol, but this is a cheapness factor on my part

I would stick with 5W30 because I assume 1997 engine is over 150k miles
As an engine ages the bearing gaps get larger

Oil pressure is the BACK PRESSURE of the oil that is built up in the main oil passage from the pump
As the bearing gaps get bigger more oil can pass thru them so less back pressure, so lower oil pressure

w30 is a viscosity rating, its thicker than w20, so w30 passes thru the bearing gaps slower and keeps oil pressure higher

I run 10w40 in my 400k mile 4.0l engine for this reason, and regular oil as I do have some leaks, lol