Hey fellas, been busy with school and work and family. Hope everyone is well here! So, crazy story happened with these two oils. AFIK, my truck has always had a diet of Rotella. I have used 10w-30 and 15w-40, but mostly the 15w-40 has been fine for my needs. This last summer we took our bi-annual trip to Texas and when visitng a friend of mine, he said he has been using the Motorcraft 15w-40 in all of his older 7.3s and it works great etc, not to mention, it is actually a bit cheaper than Rotella at WalMart AND they offer it in 10w-30 should ever have the need or desire, right? I also figured, hey, its designed for the Powerstroke which is heavily dependent on good oil for the fuel systems; mainly injector performance. I promptly changed it when I was at his house and we headed back to California 2 days later. Long story short, my truck started missing and stumbling under WOT and would not run very well unless I sort of gave it only 1/2 throttle. It would have good power, stumble, good power, miss, miss, stumble, and so forth. When I got home, it continued to do this for the last two weeks and I thought it was injector time for sure. HPOP was good with pressure and all else was in order with the rest of the truck. I told my buddy about it and he asks, "did this start after you switched over to Motorcraft?" I said "yep"! He tells to change back to Rotella and get back to him with the results. I am here to tell you that when I changed it and started the truck,as soon as the oil circulated I could tell a huge difference in the idle cadence! I drove it and it was like a new truck! It had its power back, no missing, and ran like it just got a new set of injectors. I could not believe it. I thought it might be a fluke, but a week later, it has not missed one time. It accelerates super smooth and my mileage is back up. I guess I say all this to say that I really learned how important oil is to HEUI systems. I am NOT saying one oil is better than the other because I know plenty of guys who run Motorcraft Diesel oil religiously and have great results. My truck happened to be one that just didn't like it for WHATEVER reason. I never even considered oil being a problem when my injectors were not working as they should. Once I talked about this on the Ford forum, a few others popped up and said the same thing. they found out that their trucks literally run better on Rotella or Delvac or whatever their truck got used to than it did on whatever oil they tried to change over to. Again, this is not about Rotella vs. everything else. I have used every diesel oil under the sun with good UOAs, but this is a first for me. Even Supertech has been used in my trucks with good results Yep, I said it. Anyways, that's my story. thanks for reading!!
Last edited by a moderator: