I have 106,550 miles on my 3.9, what is the best oil for me that may help with gas mileage!

 

Stick with what the manufacturer recommends in the owners manual.

 

I use 10/30 conventional oil, mostly brand name stuff that's on sale at my favorite oil supplier for 6 vehicles....Wal-Mart. I would think it's more important to do frequent oil changes rather then worry about the brand too much. I have 250K on the clock and the motor is clean. I did run some seafoam in the oil and gas recently to keep things tidy. I also like to add a little marvel mystery oil cause the engine is so old. Quiet and still runnin strong! Everyone has their opinion on oil though, this is just mine.

 

I am of the same belief in keeping my oil changed within every 3 to 4000 miles is more important than than which brand I use. I'm new to this truck and I've looked it over and over and there's nothing stating what weight oil is recommended for this truck! So I went with 10w30 Pennzoil high mileage, but I'm starting to think I messed up! It says a bunch of crap about sealing leaky **** and cleaning out sludge, my truck has neither of those! Burns no oil, leaks nothing and it's clean internal! Pulled valve covers when I bought it to see how it had been treated by its original owner, he took great care of it, all maintenance records were sent to me when I ask him for them. I'm just wanting to continue to care for it as he had. But finding info that I can trust has been alittle difficult so far, I'd like to change all the fluids and have the confidence that my truck will be ready to drive cross country if that's what I need to! So so long winded, and thanks for any knowledge that's shared!

 

No oil is going to make a noticeable difference in mileage to the individual. Manufacturers may see a difference for an entire fleet (read up on CAFE standards), but to the individual, don't bother chasing that ghost. Good tire pressure and plugs do a lot more for mileage, along with driving habits.


I run full syn QSUD 5W-30 in my 4.7L and I change it anywhere between 6 - 7.5K. The oil is still very clean on the stick, so I could probably go further. I burn no oil either.