EDGE-CUTTING 5V4696 - Caterpillar

These engines have a pressure type cooling system. A pressure type cooling system provides two advantages. The cooling system can have safe operation at a temperature that is higher than the normal boiling point of water. This system prevents cavitation in the water pump. It is difficult for an air or steam pocket to form in this system.If general inspections of the cooling system are not made, engine temperatures will increase. This is a common reason for increased engine temperatures. Make a visual inspection of the cooling system before a test is made with test equipment.Visual Inspection Of The Cooling System
Check coolant level in the cooling system.
Look for leaks in the system.
Look for bent radiator fins. Make sure that there is no restriction in the air flow through the radiator.
Inspect the drive belts for the fan.
Check for damage to the fan blades.
Look for air or combustion gas in the cooling system.
Inspect the filler cap and the surface that seals the cap. This surface must be clean. Testing The Cooling System
Remember that temperature and pressure work together. Check temperature and pressure when a diagnosis is made of a cooling system. Cooling system pressures will have an effect on cooling system temperatures. The chart displays this relation between pressure and temperature.
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Boiling point of waterTest Tools for Cooling System
Table 1
Tools Needed     Quantity    
4C-6500     Digital Thermometer     1    
8T-2700     Blowby/Air Flow Indicator     1    
9S-8140     Pressurizing Pump     1    
6V-3121     Multitach     1    The 4C-6500 Digital Thermometer is used to diagnose engine overheating problems. This 4C-6500 Digital Thermometer is also used to diagnose problems in an engine that has been overcooled. This group can be used to check temperatures in several different parts of the cooling system. Refer to Special Instruction SEHS8446 in order to find the testing procedure.
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8T-2700 Blowby/Air Flow Indicator The 8T-2700 Blowby/Air Flow Indicator is used to check the air flow through the radiator core. This test procedure is in Special Instruction SEHS8712.The 9U-7400 Multitach is used to check the fan speed. The testing procedure is in Special Instruction SEHS7807.Checking Pressure Cap
9S-8140 Pressurizing Pump One cause for a pressure loss in the cooling system can be from a bad seal on the radiator pressure cap.
Pressurized System: Hot coolant can cause serious burns. To open the cooling system filler cap, stop the engine and wait until the cooling system components are cool. Loosen the cooling system pressure cap slowly in order to relieve the pressure.
After the engine is cool, loosen the pressure cap and allow the pressure out of the cooling system. Then remove the pressure cap. Inspect the pressure cap carefully. Look for damage to the seal or to the sealing surface. Any foreign material or foreign deposits that accumulate on the following parts must be removed: cap, seal and sealing surface.
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Typical schematic of filler cap (1) Sealing surface of both filler cap and radiator
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9S-8140 Pressurizing Pump The 9S-8140 Pressurizing