Engine Maintenance (Rev. 04/03)
43
Checking the antifreeze
Check the solution concentration by using a temperature
compensated antifreeze hydrometer or a refractometer
designed for testing antifreeze. Maintain a minimum of 50%
permanent type antifreeze concentrate and 50% water solu-
tion to provide protection to -30 F (-34 C). Do not mix anti-
freeze stronger than 68% permanent type coolant
concentrate and 32% water for use in extreme temperatures.
Changing the Antifreeze
1. Run the engine until it is up to operating temperature.
Stop the unit.
2. Open the engine block drain and accumulator tank
drain, and completely drain coolant. Observe coolant
color. If the coolant is dirty, proceed with a, b, and c.
Otherwise go to step 3.
Accumulator Tank Drain
CAUTION: Avoid direct contact with hot coolant.
a. Run clear water into radiator and accumulator and
allow it to drain out of the block until it is clear.
b. Close the block drain and install a commercially
available radiator and block flushing agent, and
operate the unit in accordance with instructions of
the flushing agent manufacturer.
c. Open the engine block and accumulator drain to
drain water and flushing solution.
CAUTION: Avoid direct contact with hot coolant.
3. Run clear water into the radiator, and allow it to drain
out of the block and accumulator until it is clear.
4. Inspect all the hoses for deterioration and the hose
clamp tightness. Replace if necessary.
5. Loosen the water pump belt. Check the water pump
bearing for looseness.
6. Inspect the radiator cap. Replace the cap if the gasket
shows any signs of deterioration.
7. Mix one gallon of permanent type antifreeze concen-
trate meeting GM6038-M specification and one gallon
clean water in a container to make a 50/50 mixture. (Do
not add antifreeze and then add water to the unit. This
procedure may not give a true 50/50 mixture because
the exact cooling system capacity may not always be
known.)
8. Refill the radiator with the 50/50 mixture.
Antifreeze Maintenance Procedure
As with all equipment containing antifreeze, periodic
inspection on a regular basis is required to verify the condi-
tion of the antifreeze to accomplish these items. After two
years of service, inhibitors become worn out and must be
replaced by changing the antifreeze.
Every two years, the total antifreeze mixture must be
drained, flushed and replaced to maintain total cooling
system protection. When the antifreeze is replaced, use
ethylene glycol type engine coolant concentrate meeting the
GM6038-M specification. The factory recommends the use
of a 50/50 antifreeze mixture in all units even if they are not
exposed to freezing temperatures. Even in summer, the
accumulator tank can get cold enough to freeze the water in
the heat transfer coil. This antifreeze mixture will provide
To Next Page