Bearings, Bushings, Cv Joints; Universal Joints - RayTek AUTOPRO Manual De Instrucciones

Automatic A/C System (Cont.)
operation of sensors, use the IR thermometer to
measure ambient temperature near the ambient
temperature sensor and in-car temperature near
the in-car temperature sensor. Compare readings
to A/C control. If the measured and displayed
temperatures are not approximately the same, a
problem with the sensor or A/C system may exist.
Heater System
WARNING: Engine coolant can
reach temperatures exceeding
125°C (260°F). Allow engine to
cool before performing repairs on
heater system or serious injury
may occur.
Heater systems on most vehicles are connected
directly to the engine cooling system using the
engine water pump and coolant system pressure
to provide coolant to the heater core. On other ve-
hicles a separate water pump is used to circulate
water for the heater system. A heater control valve,
controlled by the A/C system, is used in some ap-
plications to stop flow of coolant into heater core
to prolong heater core life and to aid in cooling the
passenger compartment when A/C is in use. When
trouble shooting heater cores, ensure A/C system
is off and heater control valve is open as to not
stop flow of coolant to heater core. Inspect coolant
level and top off as necessary to ensure air will not
be trapped in heater core during testing.
Ensure vehicle is at operating temperature,
approximately 85-105°C (190-220°F). Verify
operating temperature has been reached by
measuring temperature at upper radiator hose
near the thermostat housing. If vehicle does not
reach operating temperature, trouble shoot the
cooling system first.
Using the IR thermometer, measure inlet and outlet
hose temperature near firewall. The temperature
reading of the inlet hose should be approximately
10°C (20°F) hotter than the outlet hose. If the out-
let hose is not hot or the temperature differential
between the inlet and the outlet hose is greater

than 10°C (20°F), coolant is not flowing through
the heater core. Check for the following:
n Plugged/Restricted heater core.
n Heater control valve not opening.

Bearings, Bushings, CV Joints

& Universal Joints
Bearings, bushings, CV joints and universal joints
all have friction surfaces that require proper clear-
ance and lubrication to operate properly. Some of
these components are sealed and do not require
service while some are equipped with fittings to
allow regular maintenance. Following manufactur-
ers recommended maintenance intervals is key to
ensuring proper operation of all friction surfaces.
Bearings & Bushings –
Including Trailers
Most bearing and bushing problems can be related
with a growl noise or metal-on-metal contact.
Once a noise is heard, damage has occurred.
A bearing or bushing that has deteriorated this
far can possibly damage the component it has
been designed to protect. To prevent this type of
damage, whenever possible, perform a through
visual inspection to check for damaged or leaking
seals. On wheel bearings, check for uneven wear
of brake pads or excessive axial movement of
wheels.
Bearings and bushings can be checked before
damage occurs. To check for deteriorating wheel
bearings, test-drive vehicle a short distance.
Stop vehicle, place in Park (auto trans) or neutral
(manual trans) and set parking brake.
Using the IR thermometer, measure temperatures
at all wheel bearings and/or hubs. The bearing or
hub with a higher temperature as compared to
other bearings/hubs will indicate potential bearing
failure. Verify that a brake drag is not causing the
difference in temperature. Inspect components
and repair as necessary.