Chrysler RAM TRUCK 2500 1994 Service Manual page 266

COOLING SYSTEM 7 - 11
COOLING SYSTEM DIAGNOSIS—DIESEL
STANDARD G A U G E
(TYPICAL)
OPTIONAL GAUGE
(TYPICAL)
L O W
TEMP.
C O N D I T I O N A N D CHECKS
DIAGNOSIS
GAUGE READING LOWs
(1) Verify gauge reading. Is a low temperature indicated?
(2) Thermostat stuck in open position?
(3) Is the gauge reading in the cold range?
(4) Low coolant level during cold ambient temperatures
(accompanied with poor heater performance).
(5) Coolant level is correct.
N o r m a l G a u g o Travel
(1) Inspect temperature gauge sending unit. Refer to Group 8,
Electrical. Repair or replace sending unit as necessary.
(2) Confirm by placing radiator thermometer in radiator.
Replace thermostat if necessary.
(3) Inspect for disconnected sending unit electrical connector
or incorrect sending unit.
(4) WARNINGS D O NOT REMOVE THE RADIATOR
CAP OF A HOT* PRESSURIZED ENGINE.
SERIOUS INJURY C A N RESULT FROM
SCALDING COOLANT*
Inspect coolant level in the coolant reserve tank and
radiator. Inspect system for leaks.
(5) Inspect heater door controls. Refer to Group 24, Heating
and Air Conditioning.
GAUGE READING H I G H . ( N O PRESSURE BLOW OFF
FROM RADIATOR PRESSURE CAP OR STEAM FROM
COOLANT RESERVE/OVERFLOW TANKJs
(1) Verify gauge reading. Is a high temperature reading
indicated?
(2) Gauge reading high without signs of boiling.
(3) Low coolant level in radiator and coolant reserve tank.
(4) Coolant level in radiator is low, but not low in coolant
reserve tank.
H i g h G a u g o Roading—Hot W o a t h o r — H o a v y Load
(1) Compare gauge reading to High Gauge Reading
illustration above.
(2) Inspect for grounded gauge, sending unit or circuit.
Refer to Group 8 , Electrical.
(3) a —Fill to full.
b — - Inspect for leaks in system and repair as necessary,
c — Ensure radiator pressure cap was shut tight. Verify
proper operation of the radiator cap upper and
lower seals.
(4) a - F i l l to full.
b — Inspect for leaks in the system and repair as necessary,
c — Inspect for leaks in the coolant reserve tank to
radiator hose,
d — Verify proper operation of the radiator cap .upper
and lower seals.
J9407-8