1942 - 1947 Chevrolet Shop Manual



	6-49

	All fans are of the four-blade type, and the specified fan should be used on each individual model to provide adequate cooling. The truck fan blade is larger than that used on the passenger engines. The fan belt drives the generator as well as the fan and water pump. The fan belt tension should be such that the belt may be moved up and down a total distance of1-1/2" at a point midway between the fan pulley and the generator pulley. A fan belt too tight will place excessive strain on the water pump and generator bearings. If the belt is too loose it will slip and affect the operation of both water pump and generator. ANTI-FREEZE SOLUTIONS In selecting an anti-freeze solution for winter operation, the local conditions and the type of service must be considered. The following information is given to enable the individual owner to more intelligently select the anti-freeze solution best suited to meet his own conditions. The available commercial materials for preparing anti-freeze solutions for automobile radiators are denatured alcohol, methanol (synthetic wood alcohol), distilled glycerine and ethylene glycol. Denatured Alcohol and Methanol Denatured alcohol and methanol solutions are quite generally used as anti-freeze solutions. Denatured alcohol and methanol are widely distributed, afford protection against freezing, and are not injurious to the materials used in the cooling system. There are two principal objections to denatured alcohol and methanol. Both are lost by evaporation, especially on heavy runs, and unless the solution in the cooling system is tested periodically, and sufficient anti-freeze added to replace the loss by evaporation, the motor or radiator, or both are likely to be damaged by freezing. The car finish is damaged by contact with denatured alcohol or methanol solutions or vapors, and any of this material accidentally spilled on the finish should be flushed off immediately with a large quantity of water. Methanol, for anti-freeze purposes, is sold in the United States in the correct concentration to give the same protection against freezing as denatured alcohol. Glycerine and Ethylene Glycol Distilled glycerine and ethylene glycol solutions are, in first cost, more expensive than alcohol but, since they are not lost by evaporation, only water need be added to replace evaporation losses. Any solution lost mechanically , such as by leakage,	foaming, etc., must be replaced adding more antifreeze solution. These solutions, under ordinary conditions, are not injurious to the car finish. The cooling system capacity on all passenger cars is 15 quarts; on all conventional trucks 14 quarts; C.O.E. trucks 16.5 quarts. NOTE—Conventional trucks equipped with the heavy duty radiator core have a capacity of 16 quarts. The increase in cooling system capacity when a heater is used must be taken into consideration when making up anti-freeze solutions. Adding Anti-Freeze While it is not a necessity in all cases that a cooling system be completely conditioned, flushed out, cleaned, reverse-flushed, etc., when anti-freeze is to be added, it is very essential to make certain checks and do certain things to at least insure the anti-freeze remaining in the cooling system. To be certain that the solution will not leak out and be lost entirely, resulting in little or no protection against freezing; or seep into the working parts of the engine, which may in some instances prove very expensive from the standpoint of either disassembly of working parts and through cleaning or replacement of parts. 1. Drain the entire cooling system including the cylinder block. If considerable rust, scale, oil or grease is present in the water drained out it is advisable to flush and clean the system thoroughly as outlined under "Care of the Cooling System" in this Shop Manual. 2. Tighten all cylinder head bolts according to the sequence shown in Fig. 64. 3. Check the water pump for leaks, excessive end-play or looseness of the shaft in the pump. This should be done carefully because anti-freeze solutions will in many instances leak or seep through where water would not. Should the water pump leak or indicate that leakage would occur with anti-freeze in the system, it should be replaced. 4. Inspect fan belt. Replace if badly worn Adjust fan belt to proper tension—allow 1-1/2" total movement up and down on that part of the belt between the top of the generator pulley and top of the fan and water pump pulley. 5. Inspect all radiator and heater hoses—if collapsed, cracked or in any way indicate a rotted condition on the inside, replacement should be made. Carefully check and tighten all hose clamps. 6. Check the thermostat. Make sure it does not stick shut or open and that it opens at the