VIII. SERVICE AND MAINTENANCE Cooling System COOLANT TYPE - Your cooling system should always be sufficiently charged with an adequate mixture of antifreeze and water, regardless of the climate, in order to maintain a broad operating temperature range. Your cooling system has been factory-charged with an ethylene glycol-based antifreeze.
NOTE: FIG 8.4
Ethylene glycol-based antifreeze and propylene glycol-based antifreeze should never be mixed.
CHECKING CONCENTRATION - The radiator cap is located immediately behind the rear of the cab (fig. 8.4). Never remove a cap from a hot engine. Always allow the engine to cool before servicing cooling system. A 50/50 antifreeze/water mixture is a conservative mixture which allows good protection against both overheating and freezing. If a stronger antifreeze mixture is required, be sure not to exceed the engine manufacturer’s guidelines for antifreeze mixing. The table in figure 8.6 gives a few examples of ethylene FIG 8.5
glycol antifreeze/water mixture protection values. Consult the engine manufacturer’s handbook for further information. Concentration should be checked every 500 hours or at the
Ethylene Glycol
40%
-23ºC
-10ºF
beginning of each winter, whichever comes first. It should be checked using a refractometer; “floating ball”-type density testers or hydrometers are not accurate enough for use with
50%
-37ºC
-34ºF
60%
-54ºC
-65ºF
FIG 8.6
heavy duty diesel cooling systems.
