I have an IH 826 tractor (D-358 engine) with over 8,000 hours. Last year, I switched it from straight 30 (the Case/IH brand) to Shell Rotella-T 15W-40. Oil consumption went from over a quart every 4-6 hours of hard work to much less than half a quart over the same period. Operating conditions are largely the same, as is the OCI (annually at about 60 hours). I haven't had this tractor all that long, but in recent years with its PO, it didn't work very hard compared to now (sickle mower vs heavy tillage). It also had an annual change previously but probably more hours. I'm sure the heavier oil helps, but I have learned from other owners that this engine (built by Neuss in Germany) prefers hard work and rpms over idling and no load stuff. If true, perhaps the operating conditions are more condusive to lower oil consumption. Comments?
Fuel consumptin is great too and has actually been improving every year. 4.5GPH first year, 4.1 last year and 4.0 this time over the same jobs and ground. I guess even old tractors get "buff" with exercise!