Originally Posted By: ARCOgraphite
Detroits dont use monogrades?
We used straight 40 weight Pennzoil, CD, I think, in the model 71s and model 92(Silver 92s) but when the series 60 came out, we got one of the first ones and my Dad was all nervous about what to use in it and thats when they suggested Mobil, which they went on was specially designed for that engine and so on... anyway, we eventually went back to Pennzoil and it was Long life 15w40 and we used that stuff in everything, three wheelers, vans, motorcycles, cars, trucks etc... all in Pennsylvania with the harsh winters, that why it cracks me up how people think 10w30 is too thick, when we ran everthing on 15w40 for years with no problems.