3-8 COOLING SYSTEM
Cooling System Pressure Testing
During pressure testing, do not exceed the pres-
sure for which the system is designed. The maxi-
mum pressure is 123 kPa (1.25 kgf/cm², 18 psi).
Remove the meter instruments (see Meter Instruments
Removal in the Electrical System chapter).
Remove the radiator cap, and install a cooling system
pressure tester [A] on the radiator filler neck.
Wet the cap sealing surfaces with water or coolant to
prevent pressure leaks.
Build up pressure in the system carefully until the pres-
sure reaches 123 kPa (1.25 kgf/cm², 18 psi).
Watch the gauge for at least 6 seconds. If the pressure
holds steady, the system is all right.
If the pressure drops and no external source is found,
check for internal leaks. Droplets in the engine oil indicate
internal leakage. Check the cylinder head gasket and the
cylinder liner O-rings.
Remove the pressure tester, replenish the coolant, and
install the radiator cap.
Over a period of time, the cooling system accumulates
rust, scale, and lime in the water jacket and radiator. When
this accumulation is suspected or observed, flush the cool-
ing system. If this accumulation is not removed, it will clog
up the water passages and considerably reduce the effi-
ciency of the cooling system.
Drain the cooling system.
Fill the cooling system with fresh water mixed with a flush-
Avoid the use of a flushing compound which is
harmful to the aluminum engine and radiator.
Carefully follow the instructions supplied by the
manufacturer of the cleaning product.
Warm up the engine, and run it at normal operating tem-
perature for about ten minutes.
Stop the engine, and drain the cooling system.
Fill the system with fresh water.
Warm up the engine and drain the system.
Repeat the previous two steps once more.
Fill the system with a permanent type coolant and bleed
the air from the system (see Coolant Filling).
Coolant Filter Cleaning
Refer to the section of carburetor in Fuel System for the