Operation and maintenance manual

QSB4.5 and QSB6.7 Cooling System
Section 5 - Maintenance Procedures at 500 Hours or 6 Months Page 5-3
Drain
WARNING
Do not remove the pressure cap from a hot engine.
Wait until the coolant temperature is below 50°C
[122°F] before removing the pressure cap. Heated
coolant spray or steam can cause personal injury.
Position the vehicle or equipment on a level surface.
Isolate the engine from the vehicle cooling system by
closing coolant flow valves to the equipment heating
systems before initiating repair. This will prevent the
heater circuit from draining, minimizing the chance for air
pockets to be present during the fill process. Refer to the
OEM service manual for system isolation valve locations.
This air can be very difficult to purge in some applications
that have several feet of plumbing and multiple heater
cores.
NOTE: If the coolant is being changed, or if the cooling
system is being flushed, it is desirable to leave the coolant
flow valves to the equipment heating systems open, in
order to completely drain the system.
Use the OEM service manual for any special coolant drain
and fill requirements.
These special instructions can also be located near the
cooling system access or fill door on the vehicle.
Remove all cooling system fill caps to allow the coolant to
drain completely.
WARNING
Coolant is toxic. Keep away from children and pets. If
not reused, dispose of in accordance with local
environmental regulations.
Drain the cooling system by opening the drain valve on
the radiator and opening the drain valve on the bottom of
the engine oil cooler housing. A drain pan with a capacity
of 57 liters [15 gal] is adequate for most applications.
After the cooling system is completely drained, close the
drain valves. Refer to the OEM service manual for
complete cooling system drain information.
Check for damaged hoses and loose or damaged hose
clamps.
Check the radiator for leaks, damage, and buildup of dirt.
Clean and replace as required.