Hydraulic wear in mobile machines often starts not with metal-to-metal contact, but with micro-dieseling: tiny air bubbles pulled in at the suction side compress and heat as they pass the pump, forming varnish that sticks spools and makes valves sluggish. Cold starts make it worse because thicker oil holds entrained air and aggravates inlet losses. Two simple mitigations are often missed: keep suction strainers coarse and short, and use a fluid that balances viscosity stability with fast air release and water separation. The same principle applies to HVLP46, especially when equipment shuttles between a cold yard and warm work.