0772346 JOHNSON SPARK PLUG, Champion QL78YC-SS (Stainless Steel)

Add coolant slowly to a hot engine to prevent possible cracking or distorting the cylinder head.
Most commercial antifreeze solutions contain rust inhibitors, however, it is recommended the adding of Caterpillar Coolant System Inhibitor to glycol base antifreeze if protection is for temperatures above -20°F (-29°C). If protection is for temperatures -20°F (-29°C) or below, do not add inhibitor. Follow instructions given on the container.
Inhibitor contains alkali. Avoid contact with eyes. Avoid prolonged or repeated contact with skin.
If a loss of coolant is noticeable, check for leaks in the system. After filling the system, start the engine and recheck the coolant level after normal operating temperature is reached. Running the engine at operating temperature will permit the thermostat to open and allow the coolant to circulate through the entire system and purge air from the engine.CLEANING THE RADIATOR: Every 10,000 miles clean dirt and trash from between the tubes of the radiator which may cause excessively high operating temperature. Wash, brush or blow the dirt out with whichever method is available and most effective.CLEANING THE COOLING SYSTEM: Clean the cooling system periodically. Mineral deposits can cause serious engine damage by retarding the transfer of heat to the coolant. A deposit of lime 1/32 inch thick insulates the same amount as 2 inches of steel, reducing the heat transfer substantially. Loose scale and sediment deposited in the cooling system will reduce circulation, resulting in possible engine damage. To clean, stop the engine when it is at normal operating temperature and drain as quickly as possible. Flush thoroughly, then fill with a solution of one pound of Oxalic Acid or Sodium Bisulfate per five gallons of water. Run the engine at operating temperature one-half to one hour, then drain and flush until water is clear. Fill with a solution of one-half pound of Sal Soda per ten gallons of water and run the engine ten minutes. Drain, flush and fill with water, adding corrosion inhibitor or the desired amount of anti-freeze.DRAINING: The cooling system is drained by removing the radiator cap, opening the valve in the bottom of the radiator, removing the drain plugs from the water pump and from the left side of the diesel engine block.FILLING THE COOLING SYSTEM: When filling a cooling system it is essential for the system to be filled completely and air pockets elimi-Proper filling procedure is necessary to assure the cooling system is completely filled. Follow the four step recommended procedure.1. Fill the radiator without interrupting the flow of fill water.2. Start the engine.3. Complete filling with the engine running at low idle. It is important this filling be completed as quickly as possible after engine start-up.4. Before installing the radiator cap allow the engine to run at low idle for several minutes then add coolant as necessary. Warm coolant circulating in the top tank is a good indication the system is full. Make sure the system is bled of air and refilled with coolant after a short period of operation. Normally the air will purge out the air vent line leading to the top tank of the radiator.TESTING THE TEMPERATURE GAUGE: Remember that boiling point temperature and pressure go hand-in-hand and neither one can be tested logically without considering the other. For example, the effect of pressurization and altitude on the boiling point of water is shown in the chart. If overheating and loss of coolant is a problem, a pressure loss in the system could be the cause. If an overheating condition is indicated on the temperature gauge and loss of coolant is not evident, check the accuracy of the temperature gauge. Make this check by installing a thermometer with a suitable bushing into the cylinder head.
CHECKING COOLANT TEMPERATURE WITH THERMOMETERUse CAUTION when working around moving parts with the engine running.Start the engine. Partially cover the radiator to reduce air flow and cooling. The reading on the instrument panel gauge should agree with the reading on the thermometer.Testing Cooling System Pressure
The cooling system is designed to work under a pressure of 4-7 PSI (7 PSI is recommended) to allow a high heat transfer for size of radiator and fan combination. In a pressurized system, a leaking radiator cap allows loss of pressure and coolant. For a simple check of cooling system pressure, install a pressure gauge in the radiator top tank and pressurize the system. Do this by either using an air valve and external air supply, hand pump, or by operating the machine until the coolant reaches operating temperature. System pressure should rise to approximately 7 PSI, and any additional pressure should force air past the relief valve through the overflow opening. Do not allow pressure to exceed 10 PSI. The system should hold a minimum pressure of approximately 7 PSI, and pressure must remain constant with the air supply shut off or the engine running at a constant temperature.
PRESSURIZING THE SYSTEMIf the pressure isn't maintained, overflow loss can occur as cooling system temperature rises. Do not remove the cap while the system is at operating temperature. Check coolant level only when cold.If the system does not hold pressure, find the leak.Carefully inspect the radiator cap, seals, sealing surfaces and the top tank filler neck surface for damage.
RADIATOR CAPTHERMOSTAT: The opening temperature of the thermostat (bench test in atmospheric pressure) should be approximately 165 1°F (74 1°C). The thermostat should be fully open at approximately 180°F (85°C).1. Remove the thermostat from the housing.2. Submerge the thermostat and a thermometer in a pan of water as shown.3. Apply heat to the pan and stir the water to maintain uniformity.4. Observe the opening temperature of the thermostat.
WATER TEMPERATURE REGULATOR REMOVAL If the thermostat does not operate correctly, install a new thermostat.WATER HOSES: Inspect all water hoses every 10,000 miles and replace if they show signs of cracking or leaking. Periodically replace all radiator and heater hoses, as it is many times difficult to determine the condition of a water hose by visual inspection and feel. Coolant hoses are expendable items