M11 Series – Service Manual – 008-018   Cooling System

Position the vehicle on level ground.

WARNING  Check the coolant level only when the engine is stopped. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Failure to do so can cause personal injury from heated coolant spray.

Remove the radiator cap after the engine is cool.

WARNING  Coolant is toxic. Keep children and pets away. If the coolant is not going to be reused, dispose of it in accordance with federal, state, and local regulations.

Drain the cooling system as follows:

• Open the radiator draincock.
• Remove the lower radiator hose.

CAUTION  Do not use caustic cleaners in the cooling system. Aluminum components will be damaged.

The cooling system
must be clean to work correctly and to eliminate buildup of harmful chemicals.

Restore™ is a heavy-duty cooling system cleaner that removes corrosion, silica gel, and other deposits. The performance of Restore™ is dependent on time, temperature, and concentration levels. An extremely scaled or flow-restricted system, for example, can require higher concentrations of cleaners, higher temperatures, or longer cleaning times, or the use of Restore Plus™. Up to twice the recommended concentration levels of Restore™ can be used safely. Restore Plus™
must be used
only at its recommended concentration level. Extremely scaled or fouled systems can require more than one cleaning.

WARNING  Do not remove the pressure cap from a hot engine. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Heated coolant spray or steam can cause personal injury.

Remove the radiator cap.

WARNING  Coolant is toxic. Keep children and pets away. If the coolant is not going to be reused, dispose of it in accordance with federal, state, and local regulations.

Drain the cooling system.

Do
not allow the cooling system to dry out.

Do
not remove the coolant filter.

CAUTION  Fleetguard® Restore™ contains no antifreeze. Do not allow the cooling system to freeze during the cleaning operation. Engine damage can occur.

Immediately add 3.8 liters [1 gal] of Fleetguard® Restore™, Restore Plus™, or equivalent, for each 38 to 57 liters [10 to 15 gal] of cooling system capacity, and fill the system with plain water.

Turn the cab heater temperature switch to high to allow maximum coolant flow through the heater core. The blower does
not have to be on.

Operate the engine at normal operating temperatures, at least 85°C [185°F], for 1 to 1-1/2 hours.

Shut off the engine, and drain the cooling system.

Fill the cooling system with clean water.

WARNING  Coolant is toxic. Keep away from children and pets. If not reused, dispose of in accordance with local environmental regulations.

Operate the engine at high idle for 5 minutes with the coolant temperature above 85°C [185°F].

Shut off the engine and drain the cooling system.

If the water being drained is still dirty, the system
must be continually flushed until the water is clean.

CAUTION  Do not add coolant while engine is hot, engine damage can occur.

Fill the cooling system with fully formulated coolant or a 50/50 mixture of fully formulated antifreeze and good-quality water. Use a service filter to bring the coolant to the correct SCA concentration level. Consult the Fleetguard® DCA4 Service Filters and Liquid Precharge in the General Information portion of this section for the correct filter to use.

Install the pressure cap. Operate the engine until it reaches a temperature of 80°C [180°F] and check for coolant leaks.

Close the radiator draincock.

Install the lower radiator hose.

Tighten the hose clamp.

Proper mixing of coolant is required:

• Pour water into the container.
• Add low-silicate antifreeze.
• Add DCA4 liquid.
• Thoroughly blend the components.

Following the correct order for mixing the coolant will prevent additive dropout during the mixing process.

Low-silicate antifreeze
must be used at a 50:50 ratio to give adequate freezing point and boiling point protection. Also, the use of low-silicate antifreeze minimizes the chance of having a silicate gel problem.

The cooling system
must be precharged with SCA. Add 1 pint of DCA4 liquid (5 units) for each 4 gallons of coolant (1.2 units per gallon). In addition, a service coolant filter containing 1 unit of DCA4 for each 4 gallons of coolant
must be installed. This will result in a total precharge of approximately 1.5 DCA4 units per gallon of coolant. Consult the Coolant Capacity Charts at the beginning of this section for correct filter selection.

Fill the system with coolant until the level is at the bottom of the radiator fill neck.

Install the radiator fill cap.

Operate the engine until it reaches a temperature of 80°C [180°F] and check for leaks.

WARNING  Check the coolant level only when the engine is stopped. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Failure to do so can cause personal injury from heated coolant spray.

Shut off the engine, and allow it to cool.

CAUTION  Do not add cold coolant to a hot engine. Engine castings can be damaged. Allow the engine to cool below 50°C [120°F] before adding coolant.

Remove the radiator or fill cap, and check the coolant level. Add coolant, if necessary.

Check the coolant level and fill, if necessary.

CAUTION  Do not apply more than 138-kPa [20-psi] air pressure to the cooling system. The water pump seal can be damaged.

If the radiator is equipped with a pressure relief valve, plug the overflow line (1).

Install the pressure tester on the radiator fill neck or surge tank, if equipped, and apply air pressure.

Inspect the following for coolant leaks and repair, if necessary:

• Lubricating oil cooler. Refer to Procedure
  007-003
• Water pump. Refer to Procedure
  008-062.
• Air compressor head gasket. Refer to Procedure
  012-019.

Remove the pressure-test equipment, and connect the relief valve and surge tank, if equipped.