Chrysler 1998 Viper RT/10 Owner's Manual page 244

7 - 6 COOLING SYSTEM
S R
D I A G N O S I S A N D T E S T I N G
COOLING SYSTEM
Establish what "driving" conditions caused this complaint. Abnormal loads on the cooling system, such as the following may be the
problem:
1 . Prolonged Idle, Very High Ambient Temperature, Slight Tail Wind at Idle, Slow Traffic, Traffic Jams,
H i g h Speed, Steep G r a d e s :
Driving techniques that avoid overheating are;
(a) Idle with A / C off when temperature gauge is at end of normal range.
(b) Do not increase engine speed for more air flow and coolant flow because the electric motor fan systems are not responsive
to engine RPM. The added cooling from higher coolant flow rate is more than offset by increased heat rejection (engine heat added
to coolant).
2 . A i r Conditioning: Add-on or After M a r k e t :
If add-on or after market A / C is involved maximum cooling components should be installed for the model involved per
manufacturer's specifications.
Further diagnostic checks should not be required.
3. Recent Service o r Accident Repair:
Determine if any recent service has been performed on the vehicle that may affect the cooling system such as engine adjustment
(wrong timing), loose or slipping water pump belt, brakes (possibly dragging), changed parts (possibly wrong), recored radiator or
cooling system refilling (possibly under-filled or trapped air.)
If investigation reveals none of the above as cause for overheating complaint refer to the following symptom chart.
Symptom Action
Blinking Engine W a r n i n g
Light O r High Gauge
Indication — W i t h o u t
Coolant Loss
Coolant Loss
Fan Never Runs
Fan A l w a y s Runs
Hot Car ( N o t Engine)
Heat Damage
Hot Carpet, Seat, Trunk
Hot Catalytic Converter
Smoke, Burnt O d o r
Hot Engine
Crackling Sounds
Hot Smell
Severe Local H o t Spots
Coolant Color
Coolant Recovery Bottle
—Level Changes
—Coolant NOT Returning
Normal with temporary operation with heavy load, high outdoor temperatures,
and/or on a steep grade.
Improper refilling procedures can result in trapped air in the system. As the cooling system
operates the pressure cap and coolant recovery system will deaerate the cooling system.
A low coolant level will result in the Coolant Reserve Tank. Add coolant. If condition
persists see System Diagnosis.
Refer to Powertrain Diagnostic Manual for test procedure.
Normal with A / C compressor clutch engaged. Otherwise consult Electrical Group 8.
Check heat shielding, exhaust system, emission controls, ignition timing — fuel/air ratio,
misfiring.
A moderate amount of sound of heating metal can be expected with any vehicle.
However, a hot smell and/or severe local hot spots on an engine can indicate blocked
coolant passages. Inspect for plugged water passages, bad casting, core sand and plugging,
a cracked block or head, or a blown head gasket. Usually accompanied with coolant loss.
Coolant color is not necessarily an indication of adequate temperature or corrosion
protection.
Level changes are to be expected as coolant volume changes with engine temperature.
If the level in the bottle is visible through the sight window centered between maximum and
minimum mark at normal engine operating temperature, the level should return to within
that range after operation at elevated temperatures.
Coolant will not return to the radiator if the radiator cap vent valve does not function,
if an air leak destroys vacuum, or if the overflow passage is blocked or restricted.
Inspect all portions of the overflow passage, pressure cap, filler neck nipple, hose, and
passageways within the bottle for vacuum leak only. Coolant return failure will be evident by
a low level in the radiator. Bottle level should increase during heat-up.
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