2. Cooling System

Front 1

Cooling System Purpose

Back 1

Purpose: The purpose of the cooling system is to quickly raise the temperature of the engine to its normal operating temperature, and to maintain that temperature through engine cooling components and functions.

Front 2

Step 1:

Back 2

Coolant is drawn from the bottom of the radiator into the water pump. The water pump is a centrifugal type pump that is gear driven of the engine gear case. The water pump pumps coolant through the transmission cooler where heat from the transmission fluid is absorbed by the coolant (E-One – transmission cooler located under the transmission, KME – located by radiator). The coolant then enters the oil cooler, where heat from the lubrication system is absorbed by the coolant. Then the coolant passes into the water jackets in the engine block where heat in the cylinder block is absorbed. The coolant then exits the engine block and enters the thermostat housing

Front 3

Step 2:

Back 3

The temperature of the engine coolant is controlled by the two blocking type thermostats located inside the housing. The thermostat housing is attached to the right side of the cylinder head. When the coolant temperature is below 185 F, the thermostats valves remain closed and block the flow of coolant from the engine to the radiator. During this period, all of the coolant in the system is reticulated through the engine and is directed back to the suction side of the water pump via a bypass tube. This recirculating of coolant aids in engine warm up.

Front 4

Step 3:

Back 4

When the temperature is between 186 -193 F, the thermostats partially open and coolant flows to the water pump and the radiator. At temperatures above 207 F, the thermostat valves are fully open, the bypass system is blocked off, and the coolant is directed through the radiator. Before the coolant flows back to the radiator, it passes through an auxiliary cooler (pump cooler). Inside the auxiliary cooler water from the fire pump is allowed to absorb heat from the coolant before it enters the radiator. The engine cooling system and fire pump are two separate systems and the fluid from either never mixes together. A valve on the Engineers pump panel allows fire pump water to enter the auxiliary cooler and “bathe” over the tubes containing the heated coolant. The auxiliary cooler is an add on device to aid in troubleshooting and maintaining a working motor during an emergency operation.

Front 5

Step 4:

Back 5

When the coolant enters the radiator, it passes through a series of tubes attached to fins, where the fluid is cooled, by air forced through the radiator. The air is forced through the radiator by the force of driving and by the fan. The engine cooling fan is mounted at the front of the engine and is belt driven from the crankshaft pulley. On most applications, the fan is thermostatically controlled. This fan assembly is designed to regulate the fan speed and maintain an efficient engine coolant temperature regardless of the variations in the engine load or outside temperature. No adjustment of the thermostatic control is necessary.

Front 6

Water Pump:

Back 6

The water pump is a centrifugal pump driven by a belt connected to the crankshaft of the engine. The pump circulates fluid whenever the engine is running.

Front 7

Thermostats:

Back 7

Thermostats functions to allow the engine to heat up quickly, and then to keep the engine at a constant temperature. It accomplishes this by regulating the amount of water that goes through the radiator. The small cylinder located on the engine side is filled with wax that begins to melt around 180F, a rod connected to the valve presses into the wax; when the wax melts it expands significantly, pushing the rod out and opening the valve.

Front 8

By-Pass hose:

Back 8

re-circulates fluid back to water pump; because it has not achieved optimal working temperature.

Front 9

Pressure Control cap:

Back 9

The Radiator has a pressure control valve/cap with a normally closed valve. The cap is designed to permit a pressure in the cooling system equal to the rating stamped on the top of the cap. A cap with a “7” on the top allows the cooling system to develop 7 psi before the valve opens. This system pressure raises the boiling point of the coolant and reduces coolant loss. The maximum allowable coolant temperature, regardless of the pressure cap used, is 210 F. To prevent collapse of hoses and other parts that are not internally supported, a second valve in the cap opens under vacuum when the system cools. It also permits coolant to flow from the coolant recovery bottle to the radiator tank.

Front 10

Recovery Tank:

Back 10

As the engine temperature, the coolant and air in the system starts to expand and build pressure. The valve in the radiator pressure cap unseats and allows the coolant to flow into the coolant recovery tank. When the engine starts to cool down, the air and coolant contract, causing a void and creating a vacuum in the system. The vacuum unseats another valve in the radiator pressure cap, allowing the coolant to flow back into the radiator.

Front 11

Radiator (Heat Exchanger) & Fan:

Back 11

Radiator is a type of heat exchanger designed to transfer heat from the hot coolant that flows through it to the air blown through it by a fan. Aluminum fins that have been brazed to the aluminum tubes turbulate the wind, cooling off the fluid quicker. E5 has the coolant tank mounted to the top of the radiator with the transmission cooler mounted to the bottom.

Front 12

Coolant Filter:

Back 12

The engine cooling system filter and conditioner is a compact bypass type unit with a replaceable spin-on type element. The factory installed coolant filter is mounted on the gear case cover. A coolant filter and conditioner provides a cleaner engine cooling system, greater heat dissipation, increased engine efficiency through improved heat conductivity and contributes to longer life of engine parts. The filter filters out impurities such as sand and rust. The filter also serves to condition the coolant by softening the water to minimize scale deposits, maintain an acid-free condition and act as an rust preventive. Corrosion inhibitors are placed in the element and dissolve into the coolant, forming a protective rustproof film on all of the metal surfaces of the cooling system.

Front 13

Auxiliary cooler:

Back 13

Before the coolant flows back to the radiator, it passes through an auxiliary cooler (pump cooler). Inside the auxiliary cooler water from the fire pump is allowed to absorb heat from the coolant before it enters the radiator. The engine cooling system and fire pump are two separate systems and the fluid from either never mixes together. A valve on the Engineers pump panel allows fire pump water to enter the auxiliary cooler and “bathe” over the tubes containing the heated coolant. The auxiliary cooler is an add on device to aid in troubleshooting and maintaining a working motor during an emergency operation.

Front 14

Transmission Cooler:

Back 14

is run off torque converter. Size of radiator/heat exchanger is dependent on gear package in transmission setting. because a transmission's lubricating fluid heats up with each gear change. While not crucial for highway driving, in which gear changes are minimized, transmission oil coolers can markedly improve the performance and longevity of transmissions that are subjected to a great deal of stress. Overheated transmission oil can lead to slower gear shifts, worn seals, lower mileage, and, ultimately, premature failure.

Front 15

Oil Cooler:

Back 15

Engine oil cooler design can be split into two types — tube and fin style, and stacked-plate design. Tube and fin style oil coolers are designed so that oil circulates through cooler lines — the tubes. As the oil circulates, the lines dissipate the heat through the fins. The stacked-plate design forces oil through a series of plates, with heat extracted as air moves across the plates. This more passive design is significantly less effective at cooling oil than tube and fin.

Front 16

Troubleshooting:

Back 16

Engine over heating while driving: Driving will help cool the engine by forcing more air though the radiator. Pull over is catastrophic. Check for cooling system leaks. Engine over heating while pumping: Check gauge on the pump panel against the gauge in the cab. Activate the auxiliary cooler. Pull a pressure line and spray a mist of water in front of the radiator.