REPAIR INSTRUCTIONS

Cooling System Components Inspection

Water Pump Inspection (Fresh Water)

The water pump is a belt-driven centrifugal or impeller type, and is located on the front of the engine. The water pump pulley is belt-driven by the crankshaft pulley.

During engine operation, the impeller spins in proportion to engine speed. The spinning impeller blades create a negative pressure (suction) at the water pump inlet port and a positive pressure at the outlet port. Engine coolant is drawn into the water pump from the heat exchanger. The impeller motion forces coolant to circulate through the engine block, cylinder heads, exhaust manifold, turbocharger and back to the heat exchanger.

Inspect the water pump for coolant leaks at the shaft seal area. Check for bearing failure or other damage.

The water pump is not a field-rebuildable unit. If a pump failure occurs, exchange it for a new or remanufactured unit available through the MackPower™ Parts System.

Gear Oil Cooler Inspection

The gear oil cooler is a heat exchanger type that uses sea/lake water to cool the transmission oil. The transmission oil is pumped from the transmission through the cooler and back to the transmission reservoir. To inspect the gear oil cooler it must be removed to allow access to the raw water inlet and outlet ports of the cooler.

Using a flashlight, inspect the tubes for corrosion, excessive rust or cracks. Blocked or restricted tubes can be cleaned (rod out) using a rifle (firearm) cleaning kit or a bore brush. First circulate a cleaning solvent such as Powercool 2001 On-Line-Cleaner, or equivalent, through the tubes. Drain the cleaner. Then use a .22 caliber rod with enough extensions to push the rod completely through the tubes. Do not try to reverse direction of the rod as the brush is too large to be reversed in the tube. A pellet gun brush (.18/.19 caliber) should also work. Push the brush through each tube and blow out with compressed air. Only about half of the tubes are accessible for cleaning.

The gear oil cooler is not a field-rebuildable unit. If a gear oil cooler failure occurs, obtain a new unit available through the MackPower™ Parts System.