Coolant Flow
 | |
| Illustration 1 | g00423398 |
Cooling system schematic (1) Temperature regulator housing (2) Radiator (3) Bypass tube (4) Water pump (5) Engine oil cooler (6) Return manifold (7) Supply manifold in the block (8) Cylinder head (9) Cylinder liner | |
The water pump is driven by a gear. The water pump is located on the right hand side of the engine. The water pump supplies the coolant for the engine cooling system. The coolant is supplied to the following components:
- Engine oil cooler (5)
- Cylinder head (8)
- Cylinder liners (9)
- Air compressor (not shown)
- Coolant conditioner element (not shown)
Note: In air-to-air aftercooled systems, a coolant mixture with a minimum of 30 percent ethylene glycol base antifreeze must be used for efficient water pump performance. This mixture keeps the cavitation temperature range of the coolant high enough for efficient performance.
 | |
| Illustration 2 | g00423399 |
Typical right side of engine (1) Temperature regulator housing (4) Water pump (5) Engine oil cooler | |
 | |
| Illustration 3 | g00423400 |
Typical rear of engine (6) Return manifold | |
Water pump (4) pulls the coolant from the bottom of radiator (2) by using the impeller's rotation. The water pump is located on the right hand side of the front timing gear housing.
The water pump impeller is rotated at 1.17 times the engine speed by an idler gear. The idler gear is turned by the crankshaft gear. The water pump shaft is supported by two ball bearings. One ball bearing is located in the water pump housing. The other ball bearing is located in the front timing gear housing. The water pump impeller face is open. The impeller vane is radial. The impeller is made out of cast iron. The rear cover is an aluminum die casting. The water pump seal is a cartridge seal that is located on the inlet side of the water pump in order to provide good water flow around the seal for cooling.
The coolant is pumped through engine oil cooler (5) to supply manifold (7). The supply manifold, which is located in the cylinder block, distributes coolant around the upper portion of the cylinder liners. At each cylinder, the coolant flows from the cylinder liner to the cylinder head. The cylinder head is divided into single cylinder cooling sections. In the cylinder head, the coolant flows across the center of the cylinder and across the injector seat boss. At the center of the cylinder, the coolant flows around the injector sleeve over the exhaust port. The coolant then exits into return manifold (6). The return manifold collects the coolant from each cylinder and the return manifold directs the flow to temperature regulator housing (1). When the coolant temperature regulator is in the closed position, the coolant flows through the coolant temperature regulator. This allows the coolant to flow directly back to the water pump for recirculation by bypassing the radiator. When the coolant temperature regulator is in the open position, the coolant is directed through the radiator and back to the water pump inlet.
Supply Manifold
Cooling is provided for only the portion of the cylinder liner above the seal in the cylinder block. The coolant enters the cylinder block at each cylinder through slits in the supply manifold. The supply manifold is an integral casting in the cylinder block. The coolant flows around the circumference of the cylinder liner and into the cylinder head through a single drilled passage for each liner. The coolant flow is split at each cylinder liner so that 60 percent flows around the cylinder liner and the remainder flows directly to the cylinder head.
Temperature Regulator Housing
 | |
| Illustration 4 | g00500620 |
Typical right front side of engine (1) Temperature regulator housing (2) Coolant temperature sensor | |
 | |
| Illustration 5 | g00423403 |
Temperature regulator housing (3) Return manifold (4) Coolant temperature regulator | |
The coolant temperature regulator is a full flow bypass type that is used to control the outlet temperature of the coolant. When the engine is cold, coolant temperature regulator (4) is in the closed position. This allows the coolant to flow through the coolant temperature regulator from return manifold (3). This allows the coolant to bypass the radiator. The coolant goes directly to the water pump for recirculation. As the coolant temperature increases, the coolant temperature regulator begins to open directing some of the coolant to the radiator and bypassing the remainder to the water pump inlet. At the full operating temperature of the engine, the coolant temperature regulator moves to the open position. This allows all the coolant flow to be directed to the radiator. The coolant then goes to the water pump. This route provides the maximum heat release from the coolant. A vent line is recommended from the manifold to the radiator overflow tank in order to provide venting for the cooling system. The recommended vent line is a #4 Aeroquip.
Coolant Conditioner (If Equipped)
 | |
| Illustration 6 | g00423404 |
(1) Engine oil cooler elbow (2) Outlet hose (3) Inlet hose (4) Coolant flow to cylinder head (5) Engine oil cooler (6) Coolant flow from water pump (7) Coolant conditioner element (8) Coolant conditioner base | |
Some conditions of operation can cause pitting on critical engine components. This pitting is caused by corrosion or by cavitation erosion. The addition of a corrosion inhibitor can keep this type of damage to a minimum.
Coolant conditioner element (7) is a spin-on element that is similar to the fuel filter and to the engine oil filter elements. The coolant conditioner element attaches to coolant conditioner base (8) that is mounted on the engine. Coolant flows from the water pump through inlet hose (3) and into the coolant conditioner base. The coolant that is conditioned then flows through outlet hose (2) into engine oil cooler elbow (1). There is a constant flow through the coolant conditioner element.
The element has a specific amount of inhibitor for acceptable cooling system protection. As the coolant flows through the element, the corrosion inhibitor, which is a dry material, disperses into the coolant. The coolant and the inhibitor are mixed to the correct concentration. Two basic types of elements are used for the cooling system, the precharge and the maintenance elements. Each type of element has a specific use. Each type of element must be used correctly to get the necessary concentration for cooling system protection. The elements also contain a filter. Even after the conditioner material is dispersed, the elements should be left in the system so the coolant flows through the filter.
The precharge coolant conditioner element has more than the normal amount of corrosion inhibitor. The precharge coolant conditioner element is used when a system is first filled with new coolant. This element must add enough corrosion inhibitor in order to bring the complete cooling system up to the correct concentration.
The maintenance elements have a normal amount of inhibitor and the maintenance elements are installed at each change interval. The maintenance elements provide enough inhibitor in order to keep the corrosion protection at an acceptable level. In order to provide the cooling system with protection, maintenance elements are installed at specific intervals.
Coolant for Air Compressor
 | |
| Illustration 7 | g00501085 |
Typical air compressor (1) Outlet hose (2) Inlet hose (3) Air compressor | |
The coolant that is used for air compressor (3) comes from the cylinder head through inlet hose (2). The coolant exits the air compressor through outlet hose (1) and flows back to the cylinder head.