824 TRACTOR Cooling System Caterpillar

Cooling System

Coolants: Water used in the cooling system should be as free as possible from scale forming minerals, not softened. It is advisable to treat the available water with AVSpare Rust Inhibitor. The use of this rust inhibitor in the cooling system will prevent the formation of rust. It will also retard, and in some cases completely eliminate mineral deposits within the engine. Most commercial anti-freeze solutions contain rust inhibitors, therefore, it is not necessary to use rust inhibitors with those solutions. Your AVSpare dealer stocks AVSpare Rust Inhibitor in convenient one quart cans. Directions for its use are printed on each can.

When the temperature is below freezing sufficient anti-freeze should be used in the cooling system to prevent freezing. Various anti-freeze mixtures such as ethylene glycol (Prestone, G.M., Permaguard, Zerex, etc.) denatured ethyl alcohol, methanol (synthetic wood or methyl alcohol) and glycerine are all suitable for use. Alcohol can be used successfully but, because it readily evaporates at the normal operating temperature of the diesel engine the solution should be tested frequently - even daily - and kept up to correct strength. This loss by evaporation is objectionable but the temperature regulator should not be removed. Doing so might make the solution run cooler and save the alcohol, but is not desirable for good performance. It is essential, therefore, that the coolant be tested frequently to assure adequate protection.

Draining: The cooling system is drained by opening the radiator drain valve (1) in the radiator outlet elbow at the bottom and on the left side of the radiator.

1-Cooling system drain valve.

Filling: To fill the cooling system, pour the coolant into the filler opening until the coolant level is even with the bottom of the filler opening pipe. When filling after draining or when excessive coolant has been lost, fill the cooling system, install filler cap, and run the engine at half speed for a period of 5 to 10 minutes to purge air from the cooling s system. Check coolant level and if it has lowered, refill to the bottom of filler opening pipe.

The cooling system is equipped with a radiator top tank designed so as to trap air in the top of the tank when filling. This trapped air compresses, as the coolant expands due to heat, or is vented through a sealed pressure overflow valve. Because of this feature, the operator can fill the cooling system to the bottom of the filler opening pipe and automatically allow for coolant expansion.

Cleaning The Radiator: Every 10 service hours clean dirt and trash from in between the tubes of the radiator which may cause excessively high operating temperature. This dirt may be easily removed by removing the bolts which hold the radiator screen in place. Then wash, brush or blow the dirt out with whichever method is available and most ef effective.

Cleaning the Cooling System: Wash the cooling system periodically. To wash, 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.

Reversible Fan: The reversible fan consists of movable fan blades, which can be positioned to provide either a suction or blower fan arrangement.

As a blower fan, the air flow is directed away from operator's compartment. As a suction fan, the air flow is directed towards the operator's compartment.

To reverse fan action, each of the fan blades must be reversed. Force the fan blade inward (against spring pressure) toward the hub to disengage the tongue on the thrust washer from the locking slot in the hub. Then turn the fan blade until the tongue on the thrust washer locks in place in the alternate position.