cwsartain

I change the oil in my truck about every 5k miles and I'm running full synthetic Castrol Edge 5W-20. I'm right at the 5k again and I checked the dip stick to find that the oil is down to below the bottom dot on the dipstick. When I changed it last, I had filled it to the top dot. So down about an inch on the stick.

Is it common for these trucks to be using oil like that?

Rygi

I don't have your engine but that's been my experience with both 4.6 and 5.4. Full synthetic 5w20 to me is damn close to water consistency and flows thin as hell. I switched to 5w30 for both race and daily driving and have always been happy with it no drop in mpg or performance.

cwsartain

Did it quit using oil once you switched?

Rygi

yes. If not completely, close to it. IMO manufacturers recommend 5w20 only because they are under pressure to reach government mandated mpg goals for their line-up of vehicles. It is not the most protective weight for any engine other than if someone really still changes their oil every 3k and no one does that anymore.

diegoo.jayjay

The most protective weight will always be 5w-30. Its even better than 10w-40.\

Heres a great read: https://540ratblog.wordpress.com/201...-test-ranking/

He compares hundreds of oil against eachother, 0-40 vs 5-30 vs 0-30 etc.

cwsartain

Thanks for the info guys! I'll pick up a couple gallons of 5w-30

funford

My 2011 5.0 has used a quart of oil every 5000 miles since it was new.

Now has 74000 miles on it.

funford

I use Motorcraft 5w20 Synthetic blend oil.

Rygi

cwsartain I should add that the Motorcraft 5w20 synthetic blend mentioned above would also decrease the oil consumption or leaking as it also won't flow as thin as the full synthetic. I just prefer going the 5w30 full synthetic route. To each his own of course.

cwsartain

I just picked up two 5qt jugs of the full synthetic 5w-30 Mobil 1. I still have about a quart left of the 5w-20. Should I just throw it out or would it hurt to mix it with 7qt of the 5w-30?