Question on viscosity of motor oil.?

Ok i have a 2000 ford f-150 with the 5.4 v8.


the owner's manual suggests 5w-30, while hayne's automotive manual states 5w-20. Could using 5w-20 damage my truck?Question on viscosity of motor oil.?
im a ford technician. we always use the ford recommended viscosity. in this case its 5w30, 5w20 is used on newer engines. nothing will happen if you use 5w30 but i dont see why you would want to change the viscosity.


just use what ford recommends.Question on viscosity of motor oil.?
It won't hurt your truck, but make sure to check the oil cap on your engine, on my F150 it tells me which viscosity to use, yours may well be the same. But for what it's worth I would go with the owner's manual.





Ford wrote it, and I would trust them more than a 3rd party like Haynes, not that I'm knocking them, I love their manuals.
Viscosity refers to resistance to flow, When it is warm it will flow faster than when it is cold. 5W30 is a thicker oil than 5W20. The W stands for winter so that it is 5 hot and 30 cold. The 5W30 is the better oil.


Depending on where you live Hot climate as opposed to Cold climate.
I like to use.....Castrol GTX High Mileage Oil.....in engines as such.


No the 5W-20W will not damage anything. U may find it actually burns off a little faster between oil changes.


I like this Castrol for that reason.





http://www.castrol.com select...United States....if that is where U live..
These numbers are suggestions for likely conditions. Unless you are going to spend a lot of time in a high temperature environment, when you would be better off with the 5W-30, it really does not matter too much. In principle I would stay with manufacturer's recommendations.
While there isn't a huge difference in the multi weight viscosity, going to a thinner oil is always a risk...I would stick to 5w30 or better...