Ok folks, here is my OPINION. I have a 2003 6.0l with 165000 km on it. With multiple warranty repairs and flashes my truck now runs consistent. Besides that I have taken a multiple of samples with different oils, some syn some not. I have used RL 15w40 this summer. Before I get to that I will list the oils I have tried. Texaco Ursa 15w40, 10w30, Delo 15w40 & 5w40, Delvac1 5w40, Royal Purple 15w40, Redline 15w40, Amsoil 15w40 & 5w30hdd, Rotella 15w40 & 10w30 & 5w40, Motorcraft 15w40 & 10w30.
My maximum OCI was 8000km, the average was around 7000KM.
Which one made my engine run the smoothest?
Delvac1 5w40, Rotella 5w40, Delo 5w40.
Which one had the worst UOA numbers compared to the average of MY SAMPLES.
Amsoil 5w30hdd, I never got to sample the Ams 15w40 as it went in for the "bed plate leak" and dumped the oil and changed with MC.
RP was similiar to the Amsoil 5w30. not impressed.
The dino's all showed similiar numbers with resepect to shear and wear, but my truck would run like [censored] close to the OCI.
Redline Sheared the least but I think we are splitting hairs here. It also had one of the highest oxidation numbers, similiar to the amsoil 5w30 hdd.
Using Bypass filtration with synthetics for extended drains on this vehicle to "maximize dollar cost averaging" is [censored].
The oil might be clean but the viscosity sucks after 7000 km anyways so what is the point. You will have piece of mind though if you change out at 7k with or with out syns.
Bypass is a great option.........on something that does not have HEUI. We have a Cat 3508,805hp 34L disp., direct injection(sounds like a locomotive) 210liter base with 2 centrifuges(bypass filtration) and my OCI is extended by 4x with dino oils and sampling. Delo 15w40
I'm not an analyst nor chemist, but call me educated.
Numbers are numbers and if you apply that to this engine the 6.0l , money saved by using syns with extended drains won't be an option becuas of the shear factor.
If you want above average numbers for wear stick to the original OCI with A 5w40, It seems to have stood up best against the rest.
Some were Ci4 when I first started testing then in the last 2 years CJ4. Was there a big enough difference I could see.? NO.
We are talking in PPM parts per million here, so If one of my samples jumps a bit, no biggie, but If it was to go from 20 ppm to 3000ppm on one of the tests I'd be concerned.
So from 20ppm to 60 or 80 is not really a problem. Sometimes we tend to overthink things.
Anyways that is my take like or not..
What is in my truck right now.? Delvac1 5w40 and I'm due for an oil change and guess what's going back in.
But I did put REDLINE 75w140 in my differential!