Walmart se4lls chevron delo 15-40 or 50 i think a diesel synthetic with high levels of zinc and phosphate for $10. gallon-i ve been using it in atleast 4 cars with oil changes at 5000 miles with no problems and good results.also use a quality filter.
Be aware of the SM grade diesel oil zinc level reduction also.
Flip it over and look in the cirlce on the back if it is a SM grade 15w40 diesel then it was effected, there is still SL grade out there.
I was running 15w50 Mobil 1. Nice oil, but you do get some top end noise with it. My noise was very minor, but never the less noise.
Everyone swears with Valvoline 20W50 VR1. Im sure its probably the best conventional oil out there right now.
I changed my oil today and went with Valvoline conventional 10 W 40. No price difference, just a little thinner. NO NOISE NOW. But I will probably try the VR1 next time.