COUPLING-PUMP DRIVE 7G7013 - Caterpillar

An expansion tank is used on engines not equipped with a radiator. The expansion tank provides space for the coolant to expand and contains an opening for filling the cooling system. It also holds a reserve supply of coolant thus minimizing the possibility of air locking. A sealed pressure overflow is incorporated in the expansion tanks, on some applications, to maintain a specific pressure within the cooling system.Removal And Installation
1. Drain the cooling system.
PREPARING TO REMOVE EXPANSION TANK
1-Fitting. 2-Bolts (two). 3-Supports. 4-Tube assembly.2. Disconnect the vent line at the fitting (1).3. Remove the line to the heat exchanger, cooling tower or keel cooler.4. Install two 3/8" NC forged eyebolts and support the tank.5. Remove four bolts that fasten the tank to supports (3).6. Inspect the gasket. Install in the reverse order of removal.Disassembly And Assembly
The adapter assembly (1) and the water level gauge assembly (2) can be removed if necessary.Inspect the gaskets and assembly in the reverse order of disassembly.
DISASSEMBLING EXPANSION TANK
1-Adapter assembly. 2-Water level gauge assembly. 3-Cover assembly.Pressure Regulating Cap
A pressure regulating valve, built into the expansion tank cap, permits a limited amount of pressure within the fresh water cooling system.Due to expansion of the coolant by rising temperature, pressure will build up in the system each time the engine is started. When this pressure rises above 4 PSI, (0,28 kg/cm 2) the seal (1) is lifted off the filler neck (3) to relieve the pressure or, if the cooling system has been overfilled, to allow some coolant to escape through the overflow tube. The valve closes when the temperature of the coolant levels off and remains closed unless there is a further increase in pressure.
PRESSURE REGULATING CAP
1-Seal. 2-Vacuum relief valve. 3-Filler neck.When the temperature of the coolant falls, a vacuum will be built up in the cooling system. As soon as the pressure in the system becomes less than atmospheric pressure, the vacuum relief valve (2) opens and allows air to enter through the overflow tube. This vacuum relief valve also functions when draining the cooling system.