Preliminary Checks - Jeep 1996 Grand Cherokee Service Manual

7 - 14 COOLING SYSTEM
DIAGNOSIS AND TESTING (Continued)

PRELIMINARY CHECKS

ENGINE COOLING SYSTEM OVERHEATING
Establish what driving conditions caused the com-
plaint. Abnormal loads on the cooling system such as
the following may be the cause.
(1) PROLONGED IDLE, VERY HIGH AMBIENT
TEMPERATURE, SLIGHT TAIL WIND AT IDLE,
SLOW TRAFFIC, TRAFFIC JAMS, HIGH SPEED,
OR STEEP GRADES:
Driving techniques that avoid overheating are:
• Idle with A/C off when temperature gauge is at
end of normal range.
• Increasing engine speed for more air flow is rec-
ommended.
(2) TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.
(3) AIR CONDITIONING; ADD-ON OR AFTER
MARKET:
A maximum cooling package should have been
ordered with vehicle if add-on or after market A/C is
installed. If not, maximum cooling system compo-
nents should be installed for model involved per
manufacturer's specifications.
(4) RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been per-
formed on vehicle that may effect cooling system.
This may be:
• Engine adjustments (incorrect timing)
• Slipping engine accessory drive belt(s)
• Brakes (possibly dragging)
• Changed parts (incorrect water pump rotating in
wrong direction)
• Reconditioned radiator or cooling system refill-
ing (possibly under-filled or air trapped in system).
• Rubber and foam air seals not properly installed
to radiator or A/C condenser after a repair.
• Upper and lower portions of radiator fan shroud
not tightly connected. All air must flow through the
radiator.
NOTE: If investigation reveals none of the previous
items as a cause for an engine overheating com-
plaint, refer to Cooling System Diagnosis charts.
These charts are to be used as a quick-reference
only. Refer to the group text for information.
ZJ