Chevron Delo 400 15w-40 CI-4+ & a Mobil 1 M1-303 oil filter. 8,345 miles on the oil, & no oil added or needed. AC Delco air filter.

Aluminum, 2
Chromium, 1
Iron, 4 :ro)
Copper, 2
Lead, 2
Tin, 0
Silicon, 7
SUS @ 210, 76.3
Flashpoint, 440
Fuel, <0.5
Coolant & H2O, 0
Insolubles, 0.2

No TBN this time. At this rate, my Duramax will never wear out. Just reinforces my belief that for most people, true synthetic oil used year-round is a waste of money.

I just put 7000 miles of hard driving on my Dmax pulling a 37' 5er up to Alaska and back. I changed the oil (Delo 400)& Filter(NAPA) just before I left. Haven't seen the change oil light yet.

deadfurrow~
I second your opinion on the Delo 400 and your test results proves the point.

Let me know when ya get to 225k. Then maybe I will change from the Amsoil.

Well, needed or not, I still switch over to syn for the -30F winter cold starts! It is good to know that dino squeezings are able to give such good performance.

Thanks for the post!

John

Let me know when ya get to 225k. Then maybe I will change from the Amsoil.

You sound like a friend of mine that sells Amsoil. Guess I better just drive it straight to the junkyard when I hit 200k miles if I don't switch to Amsoil.:rolleyes: I have enough UOAs on this truck to know that synthetic doesn't give me any better wear results than conventional oil.

Well, needed or not, I still switch over to syn for the -30F winter cold starts! It is good to know that dino squeezings are able to give such good performance.

Thanks for the post!

John

Exactly. I've already got the M1 5w-40 ready for the November oil change.

I just dont believe 8300 miles is much of a test!!! Like I said , when you get the miles I have,let me know!!!!

It turned out that it wasn't much of a test. I should have run it a lot longer. I would love to see a UOA on Amsoil 15w-40 with 8300 miles on the oil, & with the by-pass filter installed.

I ran 237k miles in 4 years on my last truck, using whatever oil I found on sale, & it's still running fine. For someone like you that pulls trailers all the time, I wouldn't hesitate to recommend synthetic. But like I originally posted, for most people, synthetics are a waste of money.

With almost 100k on the engine, those numbers look awesome!!!

deadfurrow....what's your mpg's on regular oil?v's synthetic?

deadfurrow....what's your mpg's on regular oil?v's synthetic?

Basically the same. I originally thought I was getting better fuel economy when I first switched to synthetic, but that was about the same time I installed a cat delete pipe & started using BP diesel supreme most of the time. My MPGs didn't drop off any the last time I went from Mobil 1 5w-40 to Delo 15w-40.