Originally Posted By: 35445
Hey guys, I have been running she'll rotella t 15w40 in my 2001 dodge Cummins turbo diesel year round. Temperature s here range from -40 Celsius to plus 40 and since Alberta is slipping into winter again , I now want to try a 0w40 or a 5w40 Just for more protectionin the winter rather than thick 15w40 and better starting but I also want to run it year round. would 0w40 be to thin in summer ? What is my best option ? Brand ,grade . Doesn't matter about price. I was looking at going with a John Deere oil or the shell for 0w40 - 5w40 and input is good SHOW ME THE FACTS
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2) that you ask for "best", and yet demand facts, I will presume to infer you are open to real data and not blathering of marketing info
3) have you assessed the current state of you engine with a series of UOAs? To know what it "best", you'll need to understand it's current state so that any changes can be tracked. You've been using a good oil already, so can you tell us what the average and std dev values are for your specific engine?
4) what thresholds have you set for condemnation limits?
5) how do you personally define "best" in this scenario? Is it lowest wear? Highest ROI? Lowest unaided start capability? What????
6) to really know what is "best" in terms of wear, you need reams of data in micro analysis. Until you have these, and then test any competing fluid, you'll never know what it "best". Most BITOGers simply do not have the time, money and patience to do this. Do you? It can takes years and hundreds of thousands of miles, not to mention lots of money.
Again - welcome. Not knowing how long you've lurked before joining, I do ask that you fully read the "Normalcy" article on the home page as a place to start. If you do not, you have absolutely no factual way to truly determine what is "best" for your situation.