This is always one of the great posts. Everyone has an oil tip to tell you so you are still none the wiser.I have used valvoline xld for all my vehicles in the past 20 years or so. The funny thing is when you book your vehicle into a service centre for a service, you dont get what you want you just get what ever 44 gallon drum that they use, unless you tell them and buy your said oil. I finished up putting 20,50 penrite in bessie before we sold it. When purchased the now Max, the paper work from Grant said 10, 40 fuchs. Then checking through some of the receipts, i noticed 20, 50. on the invoices. So i have decided as seeing as how the motor has done heaps of ks, i am now using or putting 20,50 penrite into the fellow. I dont think any one can ever tell you the correct oil to use. just my 2 bobs worth.