1942 - 1947 Chevrolet Shop Manual



	*6-52*

	lowing the radiator to fill between blasts of air. Continue this flushing until the water from the lead-away hose runs clear. We have now reverse flushed the radiator and are ready to do the same thing with the cylinder block and cylinder head. CAUTION—Apply the air gradually as a clogged radiator will stand only a limited pressure. Attach a lead-away hose to the water pump inlet and a length of new hose to the water outlet connection at the top of the engine. Insert the flashing gun in the new hose as shown in Fig. 105. Turn on the water and when the engine water jacket is full turn on the air in short blasts. Continue this sequence until the water from the lead-away hose runs clear. If the car has a hot water heater it should be flushed out separately, Fig. 106, as rust deposits	should be replaced. A thermostat that opens too soon will cause the engine to operate at too low a temperature; if it opens too late or is sticking, the engine may overheat.


		Fig. 107—Blowing Out Radiator Core The following opening thermostats should be used for the cooling solutions indicated. Regular ................... 140° Alcohol or similar non-permanent Anti-Freeze—Not over ....... 148° Permanent Anti-Freeze ......... 166° After checking, reassemble the thermostat and water outlet connection, using a new gasket. Examine all hoses both inside and outside. If the inside is soft and rotten, replace the hose, otherwise loose particles of rubber may be carried into the radiator and block the water passages. Adjust the fan belt to the correct tension. Close the cooling system drain cocks and fill the cooling system with water. Tighten the hose connections and check all points for leaks. Check the water pump for leaks. A leaking water pump, when the engine is not running, will draw air into the system when the engine is running. This excess oxygen in the cooling system may accelerate the formation of rust as much as 900 per cent. Examine the radiator for leaks and tighten the radiator mounting bolts. After completing the reconditioning, warm up the engine by allowing it to run for 20 minutes at a fast idle (approximately 600 R.P.M.) then tighten all cylinder head bolts. It is advisable to use a tension wrench so the tension on each bolt will be equal. A tension of 75 to 80 foot pounds is recommended. After tightening the cylinder head bolts the valve clearance should be adjusted in the following manner:
	Fig. 106-Flushing Heater will build up in the heater core just as they do in the radiator. This condition will obviously reduce the efficiency of the heater. If the flushing is done in the spring and the heater will not be used until fall, it is wise to discard the hose. If the flushing is being done in the fall, replace the hose. Dirt and bugs may be cleaned out of the radiator air passages by applying the radiator core cleaner gun to the back of the core, Fig. 107. Conditioning the Cooling System After cleaning and reverse flushing, it is necessary to condition the cooling system to prevent leaks, retard the formation of rust and make sure that the engine will be properly cooled. The thermostat plays a very important part in the cooling system and before reassembly it should be checked as outlined under "Adding Anti-Freeze." item No. 6, to see that it is functioning properly. If the thermostat is opening at too low a temperature, too high a temperature or is sticking, it