SkyTrak 6036 Service Manual - Manual (Page 135)

Section 8B Cummins Engine
Model 6036/6036T S/N 9B0500 thru 14833 8B-15
• U.S.A.—Engineering Standard
GM6038-M.
• U.K.—BS 3151: 1959: Ethanediol Anti-
freeze Type B with Sodium Benzoate and
Sodium Nitrite Inhibitors
• Australia—AS 2108-1977: Antifreeze
Compounds and Corrosion Inhibitors for
Engine Cooling Systems
2. There is an advantage to using antifreeze
even when frost protection is not necessary.
Antifreeze protects against corrosion and also
raises the boiling point of the coolant. A 50
percent concentration of antifreeze is pre-
ferred, but if this much protection is not
required, a 33 percent concentration can be
used. NEVER USE MORE THAN A 65
PERCENT CONCENTRATION UNDER ANY
CONDITION. Where frost protection will
never be required, add an approved corrosion
inhibitor to clean soft water. Change the
water/corrosion inhibitor every six months or
according to the inhibitor manufacturer’s
recommendations.
• DO NOT USE HARD WATER in the
cooling system. Hard water, or water with
high levels of calcium and magnesium
ions, encourages the formation of silica
gel formations, especially after a number
of heating and cooling cycles. These gel
formations can result in loss of cooling or
heating in radiators and cab heater cores
by coating and plugging the tubes. The
formations usually deposit in the cooler
section of the cooling system, such as the
radiator bottom tank.
• USE SOFT, DISTILLED OR DEIONIZED
WATER to reduce the potential and the
severity of silicate dropouts.
IMPORTANT: If you use water without a corro-
sion inhibitor, rust will form and plug the small
holes in the head gasket. These holes are orifices
and their size is critical. Do not enlarge the size of
the orifices. To do so will disturb the coolant flow
and will not solve an overheating problem. If you
use water without a corrosion inhibitor for even a
relatively short period, the cup plugs will rust
through, allowing coolant to leak. An incorrect or
malfunctioning radiator cap can result in the loss
of coolant and the engine running hot. Any
sudden loss of coolant from a heavily loaded
engine can result in severe damage to the pistons
and cylinder bore.
NOTE: Some corrosion inhibitor mixtures contain
soluble oil which can have an adverse effect on
some types of water hose.
8B.9.2 Radiator Pressure Cap
The system is designed to use a radiator pressure
cap to prevent the boiling of the lubricant. For a
210 °F (99 °C) system use a 7 psi (48 kPa)
radiator cap. An incorrect or malfunctioning cap
can result in the loss of coolant and the engine
running hot.
8B.9.3 How to Replace Thermostat
If it becomes necessary to replace the thermostat,
Fig. 8B.38, follow these steps.
1. Preparatory steps:
• Drain 2.1 quarts (2 liters) of coolant.
• Remove the radiator hose from the outlet
connection.
• Remove the drive belt.
• Disconnect the negative battery cable.
2. Loosen the alternator link capscrew on the
bottom of the alternator. Remove the alterna-
tor mounting capscrew and lower the alterna-
tor.
3. Remove the thermostat housing, gasket, lifting
bracket and thermostat.
4. Remove the thermostat and clean the gasket
surfaces. DO NOT let any debris fall into the
thermostat cavity when cleaning gasket
surfaces.
IMPORTANT: Always use the correct thermostat
and never operate the engine without a thermo-
stat.
MA1500
Fig. 8B.38 Thermostat Housing