12 mpg? I wish! It was more like 7-8, though I did get 10 mpg on one tank. It was actually coming out of the seals because the pcv hose wasn’t hooked up. Once I fixed that it was back to regular oil usage.
I had a 1978 f250 that went through a quart a day (100 miles) of super tech 20w50. After a while of not doing an oil change, it developed a sticky lifter. I changed the oil and it went away and never came back.
I disconnect the reservoir hose on my 04 highlander and dump it out/refill at every oil change. Synthetic atf stays noticeably cleaner than conventional. I’ve got 304,000 miles on the the original rack and pump.
I had a late 90’s diesel powered GM school bus that I took on a trip once. The guy I bought it from had just ran the trans dry because of a blown cooler line. It was shifting loud and a little rough, but still functioning. After a couple of hundred miles, that loud shift turned into a loud...