Once again, NAPA has Valvoline 5w-40 Premium Blue Extreme on sale for $18.99 per gal. Many of us consider it to be one of the better oils on the market for due to superior shear protection.

It is also less than Rotella T6 at this price point.

15-40 is also on sale.

Also, if you haven't already done so, you might want to read the treads concerning the switch to the CK-4 standard for our diesel engines.

 

ford is not liking the CK-4 standard and will be coming out with their own standard. ford test show increased wear when using ck-4 as opposed to cj-4.

me personally thing ck-4 is great since it will reduce emissions.....but....they have taken a lot of the metal wear protectors out of the blend. proceed with caution.

also , check your manual to see what wieght you should be runing based on temps. for my 6.4, I'm supposed to be at 5W40 if the temps go below 20 degrees. Im also supposed to be at 5W40 since I am running pump bio. problem is if I run 5W40, my engine sounds like someone is shaking a tool box.

got to stick with 15W40 for now. might change to 5W40 after I finish my rocker replacement job.