Thoughts on lighter Oil

[HarrySanders]

I have a Duramax and am curious your thoughts on the lighter wt 5W30 Diesel oils. I know there's a lot to cover but Maybe if not too indepth you could give us an overview.

[CleviteKid]

Hello Harry,

Welcome to TheDieselPage.com! One thing we have proved over and over it that General Motors actually knows something about diesels, and makes good parts for our engines. I would not venture away from GM recommendations except in very special circumstances.

The bearings and the piston rings develop very thin films of oil, about 100 millionths of an inch thick, that separate the crank journals from the bearings and the piston rings from the cylinder walls. If the viscosity is too low, these films will be even thinner, and some metal-to-metal contact and accelerated wear will occur.

For you, special circumstances that would warrant using 5W-30 diesel oil would be relocating from Pennsylvania to Northern Maine, or North Dakota, where your truck cools to -40 degrees, and you can't plug it in, and when you do get it started you are not towing anything or putting more than 500 pounds of people and cargo inside. Then the thinner oil might help with starts, and not hurt too much at low power levels. Otherwise, stick with the manufacturer's recommendation.

Dr. Lee :cool: