5W-40 Question

[bbslider001]

Anyone using 5w-40 in their LLY Duramax engines? Is their a big difference in using 15w40 vs. the other. I know the cold flow props. are better in the 5w, but I am curious to what others may be using and their experience. Also thinking of going from Amsoil to Scaeffers...it seems easier to get. Every time I order Amsoil, the filter is back order or it takes almost 2 weeks to get my stuff.

 

[bbslider001]

Anyone?

 

[Bambam]

Originally Posted By: cowhorse01
Anyone?


Well I have an LBZ and have used 5w40 after a few runs of conventional 15w40. No issues and I have been going back and forth between using conventional or synthetic. I'm sticking with 5w40 Amsoil!

 

[Drivebelt]

There can be a small gain in fuel economy (~ 3%) by running a 5W-40 over a 15w40 in some situations, but you would likely have to be in a more northern climate to realize the saving.

Quote:
highwatstar …

It says that the fuel savings of synthetics are well documented, citing the references, and goes on to prove that a 5W-40 synthetic shows up to a 3% fuel enhancement over a 15w40 mineral oil with both lubricants fresh.

In a more recently released report, Chevron researchers differ. They say the fuel economy difference between a 5W-40 PAO synthetic and Group II 15w40 mineral oil is too small to measure. The widely respected Jim McGeehan, manager of engine oil technology, co-authored this SAE paper (2001-01-1968) that disputes the ExxonMobil findings. It was presented to a lubricants meeting just two months ago, the Chevron researchers reporting that their tests could find no statistically measurable difference between a well formulated Group II mineral-based lube and one based on a PAO synthetic.


So the fuel economy saving in one paper of the 5W-40 was disputed by another paper. The test conditions may have made the difference.

 

[D-Roc]

I have often felt as well the difference can be one company using PAO and pushing it harder...I know Chevron doesn't use full PAO for most of their oils. could have been another reason for that as well, maybe not.
I use Chevron for the low wear numbers it produces for me...If it came to fuel economy or lower wear, I will definitely take lower wear. Especially the way I run my rig...