1988 JEEP CHEROKEE coolant temperature
[x] Cancel search: coolant temperaturePage 1003 of 1378
Rear ......................................... 2.5 Pts. (1.2L)
Rear (Trac-Lok) (
4) .......................... 2.5 Pts. (1.2L)
(
1) - Capacities are recommended or calculated levels. Always use
dipstick (if available) to measure level.
(
2) - Includes 2.3 qts. for coolant recovery bottle.
(
3) - Fill to bottom of filler plug hole.
(
4) - Add 4 ozs. (118 ml) of Limited-Slip differential lubricant
additive first, then add new fluid.
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Service Labor Times
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Application Hours
2.5L
Automatic Transmission ................................... 3.5
Manual Transmission ...................................... 3.5
2.8L
Automatic Transmission ................................... 3.7
Manual Transmission ...................................... 3.7
4.0L
Automatic Transmission ................................... 3.6
Manual Transmission ...................................... 3.6
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LUBRICATION SPECIFICATIONS
LUBRICATION SPECIFICATIONS TABLE\
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Application Fluid Specifications
Automatic Transmission ......................... Dexron-IIE ATF
Brake Master Cylinder ......... DOT 3 (SAE J-1703F) Brake Fluid
Engine Coolant .......... Alugard 340-2 & Water (50/50 Mixture)
Engine Oil ( 1)
Gasoline Engine
Temperature Range
Above 30
F (-1
C) ....... SAE 20W-40 Or 20W-50 API SH/CD
Above 0
F (-18
C) ........ SAE 10W-30 Or 10W-40 API SH/CD
Less Than 60
F (16
C) .............. SAE 5W-30 API SH/CD
Drive Axles ............................... SAE 75W-90 API GL-5
Drive Axles (Trac-Lok) ( 2) ............... SAE 80W-140 API GL-5
Drive Axles (Trailer Towing) ............. SAE 80W-140 API GL-5
Hydraulic Clutch .............. DOT 3 (SAE J-1703F) Brake Fluid
Manual Transmission ....................... SAE 75W-90 API GL-5
Manual Steering Box .............. Multi-Purpose NLGI Grade 2EP
Power Steering Pump ...................... Power Steering Fluid
Transfer Case .................................. Dexron-IIE ATF
Brake Caliper Bushings ....... GE 661 or DOW 111 Silicone Grease
Caliper Slide Pins .......... GE 661 or DOW 111 Silicone Grease
Wheel Bearings ........... Mopar Multi-Purpose NLGI Grade GC-LB
Drive Shaft U-Joints ....... Mopar Multi-Purpose NLGI Grade 2EP
Steering Linkage ( 4)( 5) ...... Mopar Multi-mileage or equivalent
Ball Joints ( 4)( 6) ........... Mopar Multi-mileage or equivalent
Weatherstrip ......................... Silicone Spray Lubricant
( 1) - SAE 10W-30 SH/CD is preferred.
( 2) - Add 4 ozs. (118 ml) of Limited-Slip differential lubricant
additive when changing fluid.
( 3) - For vehicles operating under heavy-duty towing conditions,
use SAE 75W-140 Synthetic lube.
NOTE: Before using SAE 75W-140 Synthetic the old fluid must be
Page 1011 of 1378
SPA R K C O NTR O L S YSTE M
1988 J e ep C hero ke e
1988 Exhaust Emission Systems
JEEP SPARK CONTROL SYSTEMS
DESCRIPTION
Jeep vehicles use spark control devices to assist ignition
system in controlling exhaust emissions. They are Spark Control
Temperature Override (CTO) valve, Non-Linear Vacuum Regulator (NLVR)\
valve, Forward Delay Valve, Reverse Delay Valve and on 4-cylinder
engines, Vacuum Spark Control Delay Valve. System application depends
upon engine size, emissions category and vehicle model.
COOLANT TEMPERATURE SENSOR (CTS)
The coolant temperature sensor is located in the intake
manifold coolant jacket. This sensor provides a voltage signal to the
Electronic Control Unit (ECU). The ECU uses this signal to determine
engine temperature. During cold engine operation, the ECU responds by
increasing ignition advance and inhibiting EGR operation.
NON-LINEAR VACUUM REGULATOR VALVE (NLVR)
NLVR valve is used on carbureted 6.0L models. This valve
supplies vacuum advance unit with a regulated combination of manifold
and carburetor ported vacuum when engine load is low and switches to
supply only carburetor ported vacuum as load increases.
Fig. 1: Non-Linear Vacuum Regulator Valve
Courtesy of Chrysler Motors.
OPERATION
Page 1012 of 1378
NON-LINEAR VACUUM REGULATOR VALVE
There are 2 input ports on NLVR: intake manifold vacuum and
carburetor ported vacuum. One outlet port connects to distributor
vacuum unit. At curb idle, regulated vacuum is supplied to advance
unit, when manifold vacuum is high and ported vacuum is very low. See
Fig. 1.
NLVR regulates vacuum signal so it is between these 2 vacuum
source levels at idle. As engine load increases and vacuum signal is
above 7.5 in. Hg vacuum, regulator valve switches to ported vacuum
output.
FORWARD DELAY VALVE
Some engines use this valve to improve driveability and
reduce hydrocarbon emissions. Valve functions to delay effects of
sudden increases in vacuum. This prevents sudden spark advance during
deceleration.
REVERSE DELAY VALVE
Some engines use this valve to improve cold driveability and
reduce hydrocarbon emissions. Valve is installed in vacuum line to
delay effects of manifold vacuum decrease causing retarded ignition
timing.
VACUUM ADVANCE COOLANT TEMPERATURE OVERRIDE (VA-CTO)
This valve is used on carbureted 6.0L engines to improve
driveability when engine is cold. It is located in vacuum advance
circuit. When vacuum is greater at port "4" than at port "1", air
must flow through orifice to equalize pressure. This creates
momentary delay that prevents sudden decrease in spark advance. When
vacuum is greater at port "1" than at port "4", air flows freely
through check valve and pressure is instantly equalized.
TESTING
NON-LINEAR VACUUM REGULATOR VALVE (NLVR)
Connect vacuum gauge to distributor port "DIST" on NLVR.
With engine at idle speed, a vacuum reading of 7 in. Hg vacuum should
be shown. As throttle is opened and engine speed increases, ported
vacuum level should be indicated. If not, replace NLVR. See Fig. 1.
FORWARD DELAY VALVE
1) Connect external vacuum source to port on Black (or Red)
side of delay valve. Connect vacuum gauge to port on colored side of
valve.
2) Apply a constant 10 in. Hg vacuum. Note time required for
gauge pointer to move from 0-8 in. Hg.
3) If valve fails to meet time limits, replace valve. If
valve meets specifications, install so that Black (or Red) side is
toward vacuum source.
FORWARD DELAY VALVE TIME LIMITS (1)
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Valve Color Min. Time Max Time
Page 1231 of 1378
problem symptoms. For model-specific Trouble Shooting,
refer to DIAGNOSTIC, or TESTING articles available in the
section(s) you are accessing.
BASIC HEATER SYSTEM TROUBLE SHOOTING CHART
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CONDITION POSSIBLE CAUSE \
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Insufficient, Erratic,
or No Heat
Low Coolant Level
Incorrect thermostat.
Restricted coolant flow through
heater core.
Heater hoses plugged.
Misadjusted control cable.
Sticking heater control valve.
Vacuum hose leaking.
Vacuum hose blocked.
Vacuum motors inoperative.
Blocked air inlet.
Inoperative heater blower motor.
Oil residue on heater core fins.
Dirt on heater core fins. \
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Too Much Heat
Improperly adjusted cables.
Sticking heater control valve.
No vacuum to heater control valve.
Temperature door stuck open. \
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Air Flow Changes During
Acceleration
Vacuum system leak.
Bad check valve or reservoir. \
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Air From Defroster At All
Times
Vacuum system leak.
Improperly adjusted control cables.
Inoperative vacuum motor. \
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Blower Does Not Operate
Correctly
Blown fuse.
Blower motor windings open.
Resistors burned out.
Motor ground connection loose.
Wiring harness connections loose.
Blower motor switch inoperative.
Blower relay inoperative.
Fan binding or foreign object
in housing.
Fan blades broken or bent. \
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BRAKES
BRAKE SYSTEM TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
Page 1247 of 1378
Low fuel pressure Test pressure regul-
ator and fuel pump,
check for restricted
lines and filters
No distributor reference Repair ignition
pulses system as necessary
Open coolant temperature Test sensor and
sensor circuit wiring
Shorted W.O.T. switch in Disconnect W.O.T.
T.P.S. switch, engine
should start
Defective ECM Replace ECM
Fuel tank residual pressure Test for fuel
valve leaks pressure drop after
shut down
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Hard Starting Disconnected hot air tube Reconnect tube and
to air cleaner test control valve
Defective Idle Air Control Test valve operation
(IAC) valve and circuit
Shorted, open or misadjusted Test and adjust or
T.P.S. replace T.P.S.
EGR valve open Test EGR valve and
control circuit
Poor Oxygen sensor signal Test for shorted or
circuit
Incorrect mixture from PCV Test PCV for flow,
system check sealing of oil
filter cap
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Poor High Speed Low fuel pump volume Faulty pump or
Operation restricted fuel
lines or filters
Poor MAP sensor signal Test MAP sensor,
vacuum hose and
wiring
Poor Oxygen sensor signal Test for shorted or
open sensor or
circuit
Open coolant temperature Test sensor and
sensor circuit wiring
Faulty ignition operation Check wires for
cracks or poor con-
nections, test
secondary voltage
with oscilloscope
Contaminated fuel Test fuel for water
Page 1313 of 1378
VA C UUM D IA G RAM S
1988 J e ep C hero ke e
1988 Exhaust Emission Systems
JEEP VACUUM DIAGRAMS
DIAGRAM ABBREVIATIONS
JEEP VACUUM DIAGRAM ABBREVIATIONS \
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CTO .......... Coolant Temperature Override
EGR ............. Exhaust Gas Recirculation
HDC CTO ............... Heavy Duty Cooling,
Coolant Temperature Override
PCV ........ Positive Crankcase Ventilation
TAC .............. Thermostatic Air Cleaner
VSD .................... Vacuum Signal Dump
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VACUUM DIAGRAMS
Fig. 1: 2.5L 4-Cylinder
Courtesy of Chrysler Motors.