Oil Selection for hot weather

[Alan L.]

I have a Scag Wildcat with a 26hp Kawasaki liquid cooled engine, about 400 hours so far. I changed the oil in March, put 10w-30 dino oil in there and have about 40 hours since then (100 hour schedule on oil changes). Because of the 100+ heat we are having regularly I figured I needed to up the viscosity. The manual calls for 40 weight oil for over 100, 10w30 or 10w40 for 95 or so, but I don't recall ever seeing any 40 weight. I did have a couple quarts of Exxon 20w50 on hand and went ahead and used that for the oil change.

My dealer says that is all they put in them spring or summer, engine and hydraulics both (I have changed the hydraulic oil and used it for that too).

Since the manual didn't call for 20w50 could this be a problem? It was 107 a couple days ago and doesn't get down to 95 until about 9 at night and hits 95 at probably 10 in the morning.

[bp fick]

15w-40 ? Rotella? Couldn't go wrong.