I have been taking my truck into WM for oil changes the last few times. I just happened to be looking at my maintenance records the other night and noticed they listed the oil used as 5-30 bulk Valvoline ( every time I was there ).
My truck is an 05 f-150 with a 5.4 and it clearly is labeled on the oil fill cap 5-20 oil.
Is this a potential problem that I should bring to WMs attention?

I would ask them to put 5w20 in it, it is a blended synthetic oil. I have seen some engine make some noise after the wrong oil was used, so I would request the correct oil in it.

The Ford spec is 5W-20, and at least semi or partial synthetic. There are many 5W-20s out there that are straight petroleum oils that do NOT meet Ford's spec (the bulk 5W-20 used by most quick lubes is NOT Ford spec).
0W-20 synthetic also meets and exceeds the Ford specs.

Hey oilman - What year did they go to the 5w20? I have a 2000 F-150 and its states 5w30.

I am not oil man but ford started using 5w20 synthetic blend in 01

Some Ford vehicles started 5W-20 as early as 1997, most were 5W-20 in 2001, a few engines are still on 5W-30.

I believe all Ford 4.0L V-6 engines are still on 5W-30.
The Mustang 5.4L 2005-up is 5W-50 full synthetic required (I don't know who makes it, AMSOIL doesn't.)
There are a couple of other speciality Ford applications with different recommendations.

Does anyone know why ford would have these specific oils?

I think they started using it to improve fuel economy.

That was their only reason - fuel economy, at the sacrifice of engine protection.

Back in the late 1980s to 1990 all American car manufactures changed from 10W-40 to 10W-30 and 5W-30, Asian went from 20W-50 to the 10W-30 and 5W-30. Around and at this same time the precision and quality of engine manufacturing became much better. For example most bearing clearances went from around 1 1/2 thousandths to 1 or just under 1. The precision alignment of line boring also became much better. With the tighter clearances, using a lighter oil actually gave better protection.

But the latest changes, to 5W-20 - mostly around 2000 for Ford and Honda, and now recently for some Toyotas and Dodges, have NOT been driven by engine improvements. They have been driven purely by CAFE (government Corporate Average Fuel Economy dynometer tests). When you drop the viscosity of the oil by a step (from 30 to 20) you reduce the amount of effort to pump the oil. How much? Not enough that you or I could ever measure it - you need a dynometer to measure it. But when you manufacture millions of vehicles, a tiny improvement makes a difference to the car manufacturer.

But when you drop the viscosity without improving the engineering / clearances / design, you ARE going to get less protection. Ford's compromise - they require a partial synthetic to try to make up for the viscosity protection loss. But many owners don't pay attention to the minimum spec being partial synthetic, and many quick lubes look for the cheap way out and use the lesser quality, lower priced straight petroleum oils. Yes, many quick lubes advertise they meet the manufacturer requirements, when in reality they do NOT.

One that has a different reason for the viscosity drop: Dodge with their system that drops a V8 to a 4 cylinder at cruise for fuel economy. The system they use is very viscosity dependent and if you use a 30 weight you will lose fuel economy: I have heard of around a 4 mpg loss with 30 weight oil as compared to 20 weight oil.

Oilman,

Quick question then. My warranty is about go out on my 05 F150. I care more about protection than I do fuel economy, at least as much as a different oil is concerned. Could I change to 5W-30? Would it harm anything?

I would keep 5w20 in it! I am not oilman but have worked on fords for 19 years!

Personally, if it were mine I would use the 5W-30, or better yet, I would use AMSOIL's Signature Series 0W-30.

I agree with 4wandering....keep it 5w-20 and synthetic....it's funny how they say it doesn't protect as much but ford engine life keeps increasing.....hmmmmmm