WE have 2 PZ-9 Mud pumps both with D-398 Cats. 5000 PSI system with Pulsation dampeners. one motor has just under 36,000 HRS and the other had just under 28,000 HRS. both pumps are in buildings, on Skids, with a roof and two sides enclosed. set up to be slid together as a set with 2 tarps to fully enclose.