StarTech
Lawn Royalty
These Super Zs do get quite warm/hot. The one across the street uses 10w40 and like heat off an open oven door after use. And its been that way for 5 five years that I have servicing it. This is why its has an air deflector on the tail fin directing air rearwards.If you suspect metallic or other contamination, the lines and cooler must be replaced.
Probably full of air causing cavitation heating up the oil.