Bought my truck with 69k, currently has 161k. Had it a year so far. 05 F250 6.0 4x4. I've run 7000 15w40 since the day I got it. Then, a week and a half ago, I filled it with 9000 5w-40 for the cold. Not unusual to get -20 to -40 here in Wisconsin. The only oil related issue I've had with my truck was the hipo pump at 94k, which wasn't an oil issue, just bad parts. I run 17k-20k on my service intervals, but I normally run 4-5k per week. I've tested a few samples and the results have all been the same. Almost no metal contamination (indicative of wear), additive quantities are still high, absolutely no coolant, fuel, or water contamination in the oil. Everything is measured in ppm and the numbers are 0. They test viscosity, sulfur, oxidation, nitration and soot. The viscosity tested at 13.14 which is still well within a 40 weight rating. 0ppm sulfur. Normal soot is under 2%, test measured 0.3% soot. For the following two, normal levels are under 50%. My Oxidation measured at 13% and Nitration measured at 16%. Schaeffer recommends changing the oil before these two reach 100%. So honestly, I'm changing the oil sooner than I need to. I tow roughly 14k# with my truck 40% of the time transporting large fifth wheel campers.
5w40 is a full synthetic and 15w40 is a synthetic blend. I found with the 5w40, the engine starts at 0 degrees like it would if I had just shut it off. The cold seems to have no affect on the crankability of the engine with this oil. I'm really liking it. Last winter, with 15w40, my truck started at -18 without help, but not -20. I'm curious what I can do with the 5w-40.
The w in the oil weight stands for winter, not weight. 5w or 15w indicates the viscosity in the winter, or at a certain cold temp. But both being a 40 weight at 100 deg. centigrade, I don't think it really matters which you run, but my opinion may change when I sample the oil at 15k. I'm going to attempt to get 25k out of the full synthetic. My oil supplier's brother services many diesel trucks of various ages and makes in PA, and he runs Schaeffer 9000 5w40 full synthetic in most of them all year round and hasn't noticed any negative results. I buy 5 gallon pails of oil. $110 for 15w40 and $125 for the 5w40 but my brother gets the 5w40 for $115 from his supplier. If you figure out the oil cost per mile, its way better to run schaeffer oil.
Enough about oil, moving on to the Schaeffer Manufacturing Diesel Treat 2000 Diesel Premium additive. Every single ounce of fuel I've run through my truck has had schaeffer's in it. It was all the summer treat, except the one time they were out and I purchased the winter stuff. Winter stuff uses twice as much, so I used the same ratio as the summer stuff. It's $42 per gallon and treats 2000 gallons. That adds $0.02 per gallon on your fuel cost. Big deal. I put 2 ounces per 30 gallons. That's 64 full tanks of fuel, roughly. The 6.0's are very notorious for injector issues. Mine are still original and I just had them tested for :hehe: and they tested at 100%. I only put the recommended amount in the fuel, because its good for -20. Never a jell up or fuel issue, ever. My local BP sells #2 fuel all year long. They just add the summer additive in the winter for jelling up and they have never had fuel jell on them either. The winter stuff is good, but not really necessary. If it stays -30/-40 for any length of time, I add an extra ounce per 30g. Problem solved.
I believe these results are a true testament to the really high quality products that Schaeffer Manufacturing puts out. You can take it for what you want, but I am sold on the stuff. I run it in very vehicle that I own and put it in every hole that they make it for. I hope this helps with your quest to salvation. :liar: