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Thanks Chris. Crap this is confusing. Most of the recommended oils are 15-40, not much out there in the 5-40 range. Plus this seems to start with the 6.7s? Talk about tighter clearances, etc. ...
They focused on the 6.7 because that's the current motor (that's under warranty so it's all they really care about), but excessive wear is excessive wear. Maybe the 6.7 has some tighter tolerances, I don't really know. I know it doesn't have the HPOP that creates the excess shear force on the oil, and no one has tested how the new CK oils handle the shear. (at least that I've seen)
Except for soot level and EGR contamination, I'd expect the 7.3 to be harder on oil than the 6.7.
When I use T6 I have been known to add a bottle of Rislone which is a zinc and phosphorus additive.
Currently I am running Royal Purple Duralec. Is has been around 3500 miles since my last oil change and when I checked my oil it was half way between full and add. I also use a nice filter.
Well it took USPS a couple of weeks to deliver what they said would only take a couple of days, but I got my report in this afternoon. This was using the Valvoline Heavy Duty (high mileage semi synthetic) oil that is on the list.
If you really want synthetic, Valvoline Premium Blue 5w-40 is also on the list. I used to run the Valvoline Premium Blue 15w-40 in my 7.3 and it did just fine. I'll see if I can find a uoa report of the Premium Blue 15w-40 from my 7.3.
Here's a copy of the UOA from my 7.3 at 500,000 miles. It also lists other oils (15w-40) that I had run in my truck on the same report for comparison purposes.
It's pretty simple. Go to their website and request a free package to mail your oil in. They send it to you, you take a sample when you change the oil, add postage, and wait for the results.
