This clip was shot during the first hot weather test of my home built mini mulcher prototype. One of the most challenging aspects of designing a compact hydrostatic forestry mulcher is the lack of space for mounting the cooling systems. The most important factor in minimizing heat build-up is to transfer engine torque to the rotor in the range of maximum hydrostatic efficiency. Ideally the hydraulic oil pressure and flow will be in the middle of the pump/motor selections most efficient range. Also, the engine rpm should be maintained at or near max torque during maximum load. Sizing the pump to maintain the closed loop pressure well below the point of displacement reduction significantly reduces waste heat. Even so we went with two oversized hydraulic coolers and mounted them outside of the engine compartment to ensure cool running in extreme conditions. In this clip I purposely was putting the mulching head into the mud to work the machine as hard as possible. The air conditioner was on full and the ambient temperature was in the mid 30's Celsius . The second hydraulic cooler rarely came on during the 8 hour test and this machine has yet to overheat. It is often used to clear fire hazard brush and trees during hot weather burning ban periods.