Im sure you couldnt feel any difference. But in 50,000 miles when your engine starts to go to hell you will know why its written on the cap to use ONLY 5w-20. I mean its your truck but i dont understand why someone would second guess the engineers that developed this motor and tested what oil will suit this engine best. I guess i make such a big deal out of this because of my mechanic stresses to every one that these engines are so fine developed and fitted that it takes such a thin oil to get into all areas to lubricate proper.
Maybe he doesnt know what hes talking about who knows. Anyways cheers

 

"Much thinner oil to be lubricated properly"?? That'a why I use staight 5W oil

 

I just use cooking oil (Veggi is the best). Have used it in all my vehicles for the past ten years with great results.

No really, Mobil 1 5W20 is all I use for my truck.

 

A quality 5W 30 oil isn't going to hurt you engine * period *

Question: My owners manual specifies 5w20 oil. Do I really need to use 5w20 oil and why did my 2000 model year vehicle require a 5w30 oil, while the exact same engine in my 2001 model year vehicle requires 5w20 oil?

Answer: No. You do not need to use a 5w20 oil. The only reason 5w20 was specified for your engine is to increase the CAFE (Corporate Average Fuel Economy) reported to the Federal Government. CAFE is the combined average fuel economy of all of a vehicle manufacturer's product line. Minimum CAFE levels are specified by the Federal Government. In order for a vehicle manufacturer to continue selling profitable large trucks and SUV's, which typically have poor fuel mileage, and still meet mandated CAFE requirements, they must also sell smaller cars which have much better fuel economy ratings to offset the poor fuel economy ratings of the larger vehicles.

...and there are many other (oil study) articles that say the exact same thing about 20 vs. 30 viscosity

 

Anyone else use AmZoil 5w/20 synthetic. I started using this from the first oil change at 3000. Absolutely love the stuff. Just wondering if anyone had had any adverse reaction or experience to the product. Not to hijack the thread..just wondering.

 

AMEN.

I use Mobil 1 5W-30 in both trucks. No problems.

 

You wont catch me crying and running to Ford after 40,000 miles, because I won't be the one with engine problems.
I run 10W30 syn. in my 4.6, i wouldn't run anything less.
So far the odo is at 95,000 miles.

 

I was talking about some guys that are using staight 30 wieght oil. Thats insane.