5_108.bk Page 189 Thursday, October 4, 2001 11:45 AM
REPAIR INSTRUCTIONS Heat Exchanger Inspection
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The heat exchanger uses sea/lake water to transfer heat away from the engine cooling system. The engine coolant is pumped from the engine block and water manifold through the heat exchanger where it is cooled and pumped back to the block and exhaust/turbocharger. To inspect the heat exchanger it is not necessary to remove the unit from its engine bracket, but merely remove the side covers to allow access to the raw water cooling tubes. 1. Close the engine sea water seacock. 2. Drain sea water from the raw water cooling system by separating the outlet hose at the raw water pump.
Figure 246 — Heat Exchanger End Cover 1. Heat Exchanger End Cover Rubber Seal
The entire raw water cooling system will drain back through the removed raw water outlet hose. This system contains many gallons of water. Be prepared to catch the water in buckets or allow the bilge pump to pump it out of the hull. 3. Remove the center bolts from both ends of the heat exchanger and remove the covers.
The engine coolant (antifreeze) compartment of the heat exchanger does not need to be drained as the only inspection available is on the raw water side of the system.
2. Heat Exchanger End Cover Bolt
4. 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 5. The heat exchanger is not a field-rebuildable unit. If a heat exchanger failure occurs, obtain a new one through the MackPower™ Parts System.
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