5w30 vs 10w30 shouldn't make a difference. Where are you located? Might make a slight difference if you are in a cold climate.
"A vehicle's oil has to be thick, but not too thick. It is important that in the winter, the oil be thin enough to allow for the engine to start. But when the engine is warm, the oil must be thick enough to lubricate properly. That's where the numbers come into play.
Neither number corresponds to an actual 'weight,' even though that is the term most people use when referring to motor oil. The viscosity (flow resistance) is tested by allowing a small amount of oil to flow through an aperture. The quicker the oil flows, the lower the rating numbers.
The first number rates the viscosity of the oil at a temperature of 0 degrees F, mimicking cold winter weather, which is why the 'W' designation is added at the end of the first number. The second number repeats the test at 210 degrees F., or normal operating temperature for a fully-warmed engine.
The 'W' rating can be 5, 10, 15 or 20; lower numbers mean the oil is thinner in cold temperatures, necessary for icy climates. The second number rating (meant to represent normal operating temperature of an engine) can be 20, 30, 40 or 50. Warm-weather spots usually require oil in the upper end of that range that can handle extreme heat."
So essentially 5w30 and 10w30 are identical at normal operating temperature. The difference is on cold starts in cold weather.
Also, you must have a pre 08 4.7L, correct? Assuming this based on the oil weight(the 08+ use 5w20).
If you change the oil regularly you won't have any of the so called "common" 4.7L oil issues. They occur when people don't do regular maintenance. I've known a lot of people with 4.7L's (both generations) and nobody has ever had any issues at all with any of their trucks. Same goes for the hemi ram owner's I know. That's why I got a ram, I've seen so many people that I know have such good luck with them.
Breathing in and out is good enough for me.
Last edited by snrusnak; 11-22-2013 at 05:56 PM.