cooling systems part 2 Flashcards
two most common problems with cooling systems
to hot
to cold
first thing to check when trouble shooting cooling systems
coolant level
visual inspection of rad core
check for dirt a debris build up
bent tubes and fins
bent fin repair
bent fins can be repaired with a fin comb
when using compressed air to clean a rad
use low pressure
90 degrees to rad tubes and fins
keep nozzle safe distance away from tubes and fins
coolant leak checks
check for coolant puddles under unit
pressure cap may be malfunctioned or wrong cap
drive belt that is to loose will cause
water pump will not be able to drive as fast and consistently as required
drive belt that is to tight
pre mature wear of bearings on water pump shaft resulting in seal and bearing damage
excessive end play at one assembly equipped with a drive pulley
may cause the drive belt to wear uneven or fly of the pulleys
when checking cooling fans
always check when engine is shut down
when observing moving fan assembly
always stand in front or behind never stand beside or parallel with moving fan
fan blades have been known to fly off and kill techs
when removing pressure cap off rad
always cover with a heavy rag or cloth
wear gloves and keep face towards the side
remove cap slowly
when pressure testing rad
use pressure no more than 10% of rated cap psi
check for external leaks
dye can be placed in cooling system for ease of detection
if no external leaks but psi keeps dropping
an internal leak may be the cause
two indications of internal cooling leak
white smoke out exhaust
dipstick may have frothy white contamination
when testing electric temp gauge on unit
unit must be done with unit running
install a known accurate temperature sensing instrument to confirm accuracy of vehicle instrument
when trouble shooting fan clutch
fan clutch troubleshooting chart should be used
visual inspection of shutter system
check for smooth operation of linkage
lines in good condition
obstructions
when draining coolant
make sure unit I on a level surface
proper container is used for reuse or recycle
testing thermostat for proper operation
once removed thermostat should be closed at room temp
place in a container of water and slowly heat and record the tamp thermostat opens
when should thermostats start to open
within 1 degree of stamped temp and should be fully open within 12 degrees of temp
when installing thermostat
make sure temp sensing portion is facing the engine
when inspecting water pump you should pay close attention to
impellers and drive gear
when removing impeller on a water pump
use a puller and never hammer or pry on them
made from cast and can brake easy
when flushing coolant system it is good practice to
flush engine block first as coolant passages are larger and debris can be stuck in smaller cooling passage ways in rad
