Draining Cooling System; Filling Cooling System; Flushing And Cleaning; Pressure Cap - Kohler 15REYG Operation

3.6.2

Draining Cooling System

The radiator contains a coolant drain valve to drain the
cooling system. When draining the coolant, remove the
radiator's pressure cap: this will allow the entire system
to drain and will prevent air pockets from forming and
restricting coolant passage to the block.
Note: Pay special attention to the coolant level. After
the coolant drains, allow time for complete refill of
the engine water jacket. Check the coolant level
as described earlier.
3.6.3

Filling Cooling System

1. Close the radiator's coolant drain valve and tighten
the hose clamps.
Note: Do not add coolant to a hot engine. Adding
coolant to a hot engine can cause the
cylinder block or cylinder head to crack.
Wait until engine has cooled.
2. Fill the radiator with the recommended coolant
mixture of 50% ethylene glycol and 50% clean,
softened water to inhibit rust/corrosion and prevent
freezing. See Figure 3-5 for coolant capacity
Note: A coolant solution of 50% ethylene glycol
provides freezing protection to --37°C
(--34°F) and overheating protection to
129°C (265°F). A coolant solution with less
than 50% ethylene glycol may not provide
adequate
protection. A coolant solution with more
than 50% ethylene glycol can cause engine
or component damage. Do not use alcohol
or methanol antifreeze or mix them with the
specified coolant.
manufacturer's operation manual for engine
coolant specifications.
3. Operate the engine with the radiator cap removed
until the thermostat opens and the radiator upper
hose becomes hot.
4. Stop the engine and allow it to cool.
Model
All models
Figure 3-5 Coolant Capacity
26 Section 3 Scheduled Maintenance
freezing and overheating
Consult the engine
Coolant Capacity L (gal.)
11.5 L (3.0 gal.)
5. Add coolant to the radiator to just below the
overflow tube on the filler neck. See Section 1,
Service Views, for the overflow tube location.
6. Replace the radiator's pressure cap.
7. Maintain the coolant level in the coolant overflow
bottle between the High and Low markings. See
Section 1, Service Views, for the coolant overflow
bottle location.
Note: Periodically check the coolant level by
removing the radiator's pressure cap. Do
not rely solely on the level in the coolant
overflow bottle. Add fresh coolant until the
level is just below the overflow tube opening.
3.6.4

Flushing and Cleaning

For optimum protection, drain, flush, and refill the
cooling system at the interval listed in the service
schedule.
Flushing and Cleaning Procedure
1. Remove the pressure cap and open the radiator's
coolant drain valve and let the system drain
completely. Remove the pressure cap to simplify
draining.
2. Drain, clean, and flush the coolant overflow bottle.
3. Flush the system with clean water.
4. Close the radiator's coolant drain valve.
5. Fill the system with the recommended coolant.
6. Replace the pressure cap.
3.6.5

Pressure Cap

The cooling system utilizes a pressure cap to raise the
boiling point of the coolant, enabling higher operating
temperatures. If the cap leaks, replace it with a cap of the
same rating. Find the pressure cap rating in Figure 3-6.
Item
Pressure Cap
Thermostat
Figure 3-6 Pressure Cap and Thermostat Rating
Rating
97 kPa (14 psi)
91_C (195_F)
TP-6728 10/11