What motor oil do you use and why?

[jhornsby3]

I use the Rotella full synthetic. It has quieted the rattle some. I got another 1+ MPG. It's cheap at the Wallies. And I read a report by a independant oil analyzing firm that said that is the best full synthetic on the market for the light duty diesel engine. That it beats the requirements by a long shot. I'd post the report but I have changed computers twice now since I saved it.

[ToddMeister]

The 95 GMC gets Rotella T6 5W-40 synthetic, also running an Amsoil bypass filter. I run 10-12K oil change intervals, but change the PF1218 spin on every 2500 miles and add a quart.


Have been running RotellaT 15W-40 in the 2005 Dmax and 7500 mile change intervals. EGR disabled since new, oil stays clean, starting to discolor when changed at 7500 miles. Also run with the turbo vanes open during light cruise which also reduces soot in the oil.

[Mark Rinker]

Mobil Delvac black jug - 10K intervals

[rustyk]

Rotella T 15W40 mineral, 4-5K mile drain interval (8T motorhome loads the engine a lot more than a pickup or Suburban). I was a field engineer with Shell many years ago. I may consider switching to synthetic due to ULSD, but haven't seen a convincing study about the effect of ULSD.

[greatwhite]

Rotella T6 synthetic.

5W40.

Yup, I drank the cool aid:

http://www-static.shell.com/static/c...rotella_t6.pdf

[Kennedy]

Delvac 1 5w40. My 2005 just sold. It had 8,000 miles on the oil (with bypass filtration) and the oil looked like new on the stick just a bit of darkening. Golden look on the stick. Partly oil, partly filtration and even moreso mild yet strong tuning...

I've gone 12k on my 2007 with no bypass filtration.

My 2012 got Delvac 1 at 300 miles before our trip to CO

All trucks still use the factory breather/PCV system. The 2005 and 2007 will consume about a quart in 5-7k.


My 2002 uses Cenpeco Racing 20w50 (petroleum) due to the extreme naure of operation of this engine.

[moondoggie]

Rotella 5W-40 synthetic, because I can use it in everything I own except the 2 cycles. My oil change intervals are about what they were when I used non-synthetic, but I don't worry if I go a bit over.

The 6.5s use exactly the same amount of oil as when I ran non-synthetic Rotella, but the oil doesn't get as dark, as quick. Hmmm...

As my gas cars approach 150K to 250K miles, I get real lax about change intervals. Towards the end, our 02 Century was getting changed twice a year. (My son overheated it at ~ 250K. Neither he nor I realized the gauge never makes it to the red, no matter how hot it gets. So, it wasn't in the red, & he nursed it a mile to work. Head gasket, cracked head - pretty normal for a 3.1. I don't figure the car owes me anything. Was shopping for another Century when a Saturn caught my eye.)