Same here. I live between Vassar and Mayville in michigan. That in Tuscola county. By the thumb. We have seen temps in the single digits this year. One morning my thermomitor said three below. I have a little VW diesel. A 1984 Rabbit L with the 1.6litre IDI 8V SOHC. I had mobil 1 5W-40 T&S in it earlier this year. I found the five quart jugs in the flint walmart on cirunu road. I used it the oil service before last. I didnt get to flint to get it the last oil change so I just put mobil delvac 1300 super 15W-40 in it the last oil service. Since I had it on the shelve. It works good, real good. It even did good on those single digit days. I have about 2,750 on this oil service right now. I will be dumping it tommorrow. I have some mobil clean 5000 5W-30 in the garage that is CF rated so I will be dumping it in for a short oil service. I will be dumping it at about 1,500 or so. Then I will dump in mobil T&S 5W-40 in if I get some by then. If I don't have any on hand I will dump in mobil 1 0W-40 in. I also have a 2005 Kubota RTV900 with 550 hours on it. I bought it as a demo with 20'ish hours on it. The same day the dealer delivered it to my house I drained the crank and mobil 1 0W-40 in it. At the hundred hour mark I drained everything and changed filters. And its been mobil 1 0W-40 since. Haven't had any problems to speek of. And a hydraulic relief valve go bad at 437.6 hours in the transmission. Had both relief valves replaced under warrenty. I use OEM Kubota hydro filters, a wix engine oil filter, and super tech universal transmission hydraulic fluid. Not complants. I have just enough ST fluid left for the six hundred hour service. Then I will start using kubota udt maybe.