Will I ever need to change oil in my tractors? If anybody knows how strict CA. is with disposing of all fluids from the internal combustion engine I think I have a way to beat the problem. Could one change all his tractors over to Mobil 1 Syn---------they claim it goes 15K before it needs changed in cars and trucks. I dont change my car or truck oil in less then 7500 mi. even with conventional 10-40. Seems to me 15K wear and tear would take forever on a L-Head. And I think they have syn gear lube and Prestone has an extend life anti-freeze, 5 yrs-------- thats a lot of years in tractor years. When I buy a used outfit I change oil and anti freeze but after that I have never changed my anti freeze in anything and all my anti-freeze tests fine spring and fall,year after year, even when I do a water pump, hose or radiator repair I put the drain fluid back in.