CUP 2B9175 - Caterpillar

The two stage aftercooler should be inspected, cleaned or replaced at the following service intervals and engine maintenance operations:10,000 hours ... CleanTop end overhaul ... Inspect/ReplaceMajor overhaul ... Inspect/ReplaceCleaning
Cleaning should be done after every 10,000 hours of operation.The two stage aftercooler can be cleaned without removal from the engine if fouling or blockage of passages is light and has occurred over a short period of time (less than 10,000 hours). If heavy fouling and blockage of passages is suspected or evident the aftercooler should be removed from the engine before cleaning.Cleaning While Installed On The Engine
When it is determined from the performance figures of the aftercooler in operation that an internal inspection is advisable the coolant should be drained.Water Side
Remove the cooling system tubes and branch header to inspect the interior of the tubes. Use special brushes provided in 145-0316 Cleaning Kit where deposits are soft, which will occur in the majority of installations. Rotate the rod in a clockwise direction to avoid unscrewing of the brush head from the rod. The rod assembly may be attached to an electric hand drill.Air Side
The fins can be examined by removal of the air inlet adapters since deposits will gather on the leading edges of the fins. With the air inlet adapters removed most of the deposits can be brushed away with stiff nylon brushes (not wire brushes). Use of a low pressure steam jet or compressed air blower will facilitate removal of heavier deposits.Cleaning After Removal From The Engine
In particularly bad working conditions it may be impossible to clean the aftercooler thoroughly while it is installed on the engine. Remove the aftercooler and strip the unit down so that the tubestack and sideplate assembly can be immersed in a cleaning tank. When the top and bottom headers have been removed, the tubestack comprising of the sideplates, tubeplates and cooler sections can be immersed to clean the fins and descale the tube bores.Air Side
To clean the fins, immerse the tubestack in a tank containing a solution made from degreasant powder and water. The powder should be non-toxic and free from fire risk. The solution should be agitated by either raising and lowering the tubestack into the tank or by the means of a jet of steam or air, this will accelerate the washing process.Water Side
The coolant circuit should be effectively screened to reduce the partial or complete obstruction of the aftercooler tubes by debris or marine growth. Partial obstruction of the tubes causes excessive turbulence of the fluid within the tubes and rapid corrosive attack may occur. These obstructions are generally loose and can only be effectively removed by mechanical methods. The suction and delivery filters (when installed) should be inspected and cleaned at regular intervals since these can cause an apparent loss in performance of the aftercooler.The various chemical descaling processes available will remove scales consisting mainly of calcium carbonate with ease. Scales consisting of calcium sulphate or silicates may not respond to chemical cleaning, in