Thermo King MD-MT, Operator'S Manual

Page: 84 / 192

Engine Maintenance
84
Antifreeze Maintenance Procedures
As with all equipment containing antifreeze,
periodic inspection on a regular basis is required
to verify the condition of the antifreeze. Inhibitors
become worn out and must be replaced by
changing the antifreeze. Change green or
blue-green engine coolant every two years.
Change ELC (red) engine coolant every five years
or 12,000 hours (whichever occurs first).
Do not mix green or blue-green engine coolant
with ELC (red) engine coolant. See “ELC
(Extended Life Coolant)” on page 83 for more
information about ELC.
The factory recommends the use of a 50/50%
antifreeze mixture in all units even if they are not
exposed to freezing temperatures. This antifreeze
mixture will provide the required corrosion
protection and lubrication for the water pump.
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 solution to
provide protection to -30 F (-34 C). Do not mix
antifreeze 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.
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.
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 the appropriate permanent
type antifreeze concentrate 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.
CAUTION: Avoid direct contact with hot
coolant.
1. Drain
Figure 39: Accumulator Tank Drain
CAUTION: Avoid direct contact with hot
coolant.