circulation of coolant during engine warm up.
Engine overheating and loss of coolant is some times due to an inoperative thermostat. To check for this condition
remove thermostat and test by submerging in hot water noting temperature at which thermostat opens or closes. Use an
accurate high temperature thermometer for making this test.
Hose and Clamps.
Hoses and their connections must be checked regularly because they are often the source of hidden trouble and can
often times appear in good condition on the outside while the inside will be partially deteriorated. If there are any doubts
about a hose doing its job, replacement should be made. The clamps should be inspected to make sure they are strong
enough to hold a right connection.
To aid the service man in maintaining the Cooling System at top efficiency, various items of test equipment are
available. Among these are the Cooling System Tester and the Hydrometer.
1. Hydrometers. Hydrometers which are used to test freezing protection of an antifreeze solution, work on the principle
of specific gravity or weight of the antifreeze solution. They are simple to use provided they are used in the proper
manner. When using hydrometer, the solution must be warm (at least 110 degrees), the temperature and level must
be noted correctly, and the float must be able to move freely. Read only the hydrometer scale corresponding to type
antifreeze solution in the radiator. Keep hydrometer clean inside and out and treat it with the same care as given any
other precision instrument.
HYDROMETERS DO NOT CORRECTLY REGISTER THE FREEZING PROTECTION OF A MIXTURE
METHANOL AND GLYCOL BASE ANTIFREEZE. THEREFORE, ALWAYS FLUSH THE COOLANT
SYSTEM WITH THERMOSTAT REMOVED BEFORE ADDING ANTIFREEZE FOR THE WINTER.
Always use a proper inhibited coolant.
If freeze protection is required, always use ethylene glycol antifreeze.
Reinhibit antifreeze with a non-chromate inhibitor.
Always follow the manufacturer's recommendations on inhibitor usage and handling.
Do not use soluble oil.
Chromate inhibitors should NEVER be used with permanent antifreeze.
Sealer type antifreeze should NOT be used.
Maintain prescribed inhibitor strength.