1942 - 1947 Chevrolet Shop Manual



	*6-51*

	Cleaning and Reversing Flushing A good cleaning solution should be used to loosen the rust and scale before reverse flushing the cooling system. G. M. Cooling System Cleanser is an excellent preparation to use for this purpose. The following directions for cleaning the cooling system apply only with the use of G. M. Cooling System Cleanser. NOTE—Always follow the manufacturer's instructions with the particular cleaner being used. 1. Drain the cooling system and close both drain cocks. 2. Add the liquid portion (No. 1) of the cooling system cleanser. 3. Fill the cooling system with water to a level of about 3 inches below the top of the overflow pipe. 4. Cover the radiator and run the engine at moderate speed until the heat indicator reaches 180 degrees. Remove the cover from the radiator and continue to run the engine for 20 minutes. —But avoid boiling. 5. While the engine is still running add the powder portion (No. 2) of the cooling system cleanser and continue to run the engine for 10 minutes.	The next operation is the reverse flushing, using air pressure to force the water through the system. Reverse flushing is just what the name implies— flushing in a direction opposite to the normal flow of water through the cooling system. Reverse flushing is used to get behind the corrosion deposits and force them out. First remove the thermostat. Cold water will cause it to close and result in building up pressure which might cause damage. Then remove the upper and lower radiator hoses and reinstall the radiator cap. Attach a lead-away hose at the top of the radiator. Attach a piece of new hose to the radiator outlet connection and insert the flushing gun in this hose



	Fig. 104—Reverse Flushing Radiator 6. At the end of this time, stop the engine, wait a few minutes and then open the drain cocks and lower hose connection. Be careful not to scald your hands.	- Fig. 105—Reverse Flushing Engine as shown in Fig. 104. Connect the water hose of the flushing gun to a water outlet and the air hose to an air line. Turn on the water and when the radiator is full turn on the air in short blasts, al-