Motorcraft 5W20

[85_Ranger4x4]

The first number is the weight spec of the oil in very cold temperatures.. the second number is the weight spec. at operating temperature.

I use my truck as a truck, so i use 30wt minimum, but since i also have a lot of bottom end noise when using 30wt i use 20w50 and it is nice and quiet.

Thicker oil handles a load better because it won't be squished out from the crankshaft bearings as easily as lighter oils.

Since the weather around here is always mild 5w, 10w, 20w means nothing to me. its the aft number that counts.

I do get slightly better fuel mileage using 30wt over 50wt, but the noises as idle drive me nuts.

On the flipside, a thicker oil can't go where a thinner oil can... a new engine (especially a modern one) will not like that.

I pull my tractor harder than you do your pickup, 10W-30 works fine. It is a 1950's tech engine with a 20 year old overhaul, doesn't miss a beat or make any odd sounds. If you can't run the oil you are supposed to you have problems.