oil DODGE NEON 2000 Service Service Manual

Coolant flow circuit for the 2.0L engine is shown in
(Fig. 1).
During any reassembly procedures all pipe fittings
in water jacket, and water box require cleaning and
application of thread sealant for entire length of
threads.
COOLANT
The cooling system is designed around the coolant.
The coolant must accept heat from engine block
metal and in the cylinder head area near the exhaust
valves. Then coolant carries this heat to the radiator
where the tube/fin assemblies can give off the heat to
the air.
MopartAntifreeze or the equivalent is recom-
mended for optimum cooling performance and corro-
sion protection when mixed to a freeze point of -37É C
(-35É F).
COOLANT REPLACEMENT
Refer to Group 0, Lubrication and Maintenance for
schedule.
COOLANT PERFORMANCE
Performance is measurable. For heat transfer pure
water excels (Formula = 1 btu per minute for eachdegree of temperature rise for each pound of water).
This formula is altered when necessary additives to
control boiling, freezing, and corrosion are added as
follows:
²Pure Water (1 btu) boils at 100ÉC (212ÉF) and
freezes at 0ÉC (32ÉF).
²100 Percent Glycol (.7 btu) can cause a hot
engine and detonation and will raise the freeze point
to 22ÉC (-8ÉF).
²50/50 Glycol and Water (0.82 btu) is the recom-
mended combination that provides a freeze point of
-37ÉC (-35ÉF). The radiator, water pump, engine
water jacket, radiator pressure cap, thermostat, tem-
perature gauge, sending unit and heater are all
designed for 50/50 glycol.
Where required, a 56 percent glycol and 44 percent
water mixture will provide a freeze point of -59ÉC
(-50ÉF).
CAUTION: Richer mixtures cannot be measured
with field equipment which can lead to problems
associated with 100 percent glycol.SELECTION AND ADDITIVES
The use of aluminum cylinder heads, intake mani-
folds, and water pumps requires special corrosion
Fig. 1 Cooling System Operation
1 ± HEATER
2 ± HEAT UP
3 ± COOL DOWN
4 ± PRESSURE CAP
5 ± THERMOSTAT HOUSING6 ± WATER PUMP
7 ± ENGINE
8 ± COOLANT RECOVERY SYSTEM TANK
9 ± RADIATOR
7 - 2 COOLING SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

protection. MopartAntifreeze or the equivalent is
recommended for best engine cooling without corro-
sion. When mixed only to a freeze point of -37ÉC
(-35ÉF) to -59ÉC (-50ÉF). If it looses color or becomes
contaminated, drain, flush, and replace with fresh
properly mixed solution.
COOLANT RECOVERY SYSTEM
This system works in conjunction with the radiator
pressure cap to utilize thermal expansion and con-
traction of the coolant to keep the coolant free of
trapped air. The system provides space for expansion
and contraction. Also, the system provides a conve-
nient and safe method for checking and adjusting the
coolant level at atmospheric pressure without remov-
ing the pressure cap. It also provides some reserve
coolant to compensate for minor leaks and evapora-
tion or boiling losses. All vehicles are equipped with
this system (Fig. 2).
Refer to Coolant Level Check, Deaeration, and
Pressure Cap sections for operation and service.
ENGINE THERMOSTAT
The engine thermostat is located on the front of
the engine (radiator side) in the thermostat housing/
engine outlet connector. The thermostat has an air
bleed (vent) located in the flange and a O-ring for
sealing incorporate on it. There is a relief in the ther-
mostat housing/outlet connector for the O-ring.
The engine thermostat is a wax pellet driven,
reverse poppet choke type. It is designed to provide
the fastest warm up possible by preventing leakage
through it and to guarantee a minimum engine oper-
ating temperature of 88 to 93ÉC (192 to 199ÉF). Also,
the thermostat will automatically reach wide open, to
accommodate unrestricted flow to the radiator astemperature of the coolant rises in hot weather to
around 104ÉC (220ÉF). Above this temperature the
coolant temperature is controlled by the radiator, fan,
and ambient temperatureÐnot the thermostat.
A thermostats primary purpose is to maintain
engine temperature in a range that will provide sat-
isfactory engine performance and emission levels
under all expected driving conditions. It also provides
hot water (coolant) for heater performance. It does
this by transferring heat from engine metal and
automatic transmission oil cooler (if equipped) to
coolant, moving this heated coolant to the heater core
and radiator, and then transferring this heat to the
ambient air.
RADIATOR
The radiator is a down-flow type (vertical tubes)
with design features that provide greater strength,
as well as sufficient heat transfer capabilities to keep
the engine coolant within operating temperatures.
The radiator functions as a heat exchanger, using
air flow across the exterior of the radiator tubes. This
heat is then transferred from the coolant and into
the passing air.
The radiator has an aluminum core with plastic
tanks. Although stronger than brass, plastic tanks
are subject to damage by impact. Always handle radi-
ator with care.
RADIATOR COOLING FAN MODULE
The radiator cooling fan is a single speed electric
motor driven fan. The fan module includes an electric
motor, fan blade, and a support shroud that is
attached to the radiator (Fig. 3).
Fig. 2 Coolant Recovery System
1 ± RECOVERY HOSE
2 ± ENGINE COOLANT RECOVERY CONTAINER
3 ± PRESSURE CAP
Fig. 3 Radiator Fan
1 ± SCREWS
2 ± LOWER MOUNTS
3 ± FAN MOTOR ELECTRICAL CONNECTOR
PLCOOLING SYSTEM 7 - 3
DESCRIPTION AND OPERATION (Continued)

Radiator cooling fan control operation is accomplished
two ways. The fan always runs when the air condition-
ing compressor clutch is engaged. In addition to this
control, the fan is turned on by the temperature of the
coolant which is sensed by the coolant temperature sen-
sor which sends the message to the Powertrain Control
Module (PCM). The PCM turns on the fan through a
fan relay by grounding the relay's coil. The fan relay is
located in the Power Distribution Center (PDC) (Fig. 4).
Refer to the label beneath the PDC cover for location of
fan relay.
The PCM will actuate the fan relay whenever the A/C
clutch is engaged regardless of coolant temperature and
vehicle speed. If the A/C clutch is not engaged, the PCM
will actuate the fan relay when the coolant temperature
reaches approximately (97É C) 207É F and turns off the
fan relay when the coolant temperature drops to
approximately (94ÉC) 201É F. The fan relay is also
turned off when the vehicle speed is above approxi-
mately 100 Km/h (62 MPH). Refer to Group 8W, Wiring
Diagrams for circuity provided.
If the cooling fan is inoperative or a Diagnostic
Trouble Code (DTC) related to fan control has been
set, refer to the appropriate Powertrain Diagnostic
Manual for complete diagnostic procedures.
COOLING SYSTEM PRESSURE CAP
The cooling system pressure cap is located on the cool-
ant outlet housing near the front of the cylinder head.
The cooling system will operate at higher than atmo-
spheric pressure. The higher pressure raises the coolant
boiling point, allowing increased radiator cooling capac-
ity. The pressure cap will release cooling system pres-
sure in a range of 97±124 kPa (14±18 psi).
A vent valve located in the center of the cap allows
a small amount of coolant flow from the coolant
reserve system (CRS) tank. This valve is spring
loaded in the closed position. However, it must be
free to open during system cool-down.If the valve is
stuck shut, the radiator hoses will collapse on
cool-down. Clean the vent valve (Fig. 5) to
ensure proper sealing function.
There is a gasket in the cap that seals to the top of
the filler neck so that vacuum is maintained to draw
coolant back into the system from the coolant reserve
system (CRS) tank.
Fig. 4 Power Distribution Center (PDC)
RADIATOR COOLING FAN OPERATION CHART
Cooling Fan Control
A/C Off
Fan On: 97É C (207É F)
Fan Off: 94É C (201É F)Vehicle Speed >
100 Km/h (62
MPH)
A/C On
Fan OnÐregardless of coolant temperature or vehicle
speed.
Fig. 5 Cooling System Pressure Cap
1 ± PRESSURE RATING
2 ± FILLER NECK SEAL
3 ± PRESSURE VALVE
4 ± VACUUM VENT VALVE (SHOWN IN SEALING POSITION)
7 - 4 COOLING SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

AUTOMATIC TRANSMISSION OIL COOLER
Oil coolers are internal oil to coolant type, mounted
in the radiator lower tank (Fig. 9). Rubber oil lines
feed the oil cooler and the automatic transmission.
Use only approved transmission oil cooler hose. Since
these are molded to fit space available, molded hoses
are recommended. Tighten Oil Cooler Hose Clamps
to 2 N´m (18 in. lbs.).
ACCESSORY DRIVE BELTS
The accessory drive consist of two Poly-V type
drive belts (Fig. 10). One belt drives the generator,
the other drives the power steering pump and air
conditioning compressor (if equipped). The power
steering/air conditioning belt is tensioned by an auto-
matically controlled belt tensioner. The generator
belt is manually tensioned using an adjusting bolt
and a locking nut.
ENGINE BLOCK HEATER
The heater is mounted in a core hole (in place of a
core hole plug) in the engine block, with the heating
element immersed in coolant (Fig. 11). The engine
block heater is available as an optional accessory.
The heater is operated by ordinary house current
(110 Volt A. C.) through a power cord and connector
behind the radiator grille.
When in operation, the engine block heater can
provide easier engine starting and faster warm-up,
when vehicle is operated in areas having extremely
low temperatures.CAUTION: The power cord must be secured in its
retainer clips, and not positioned so it could con-
tact linkages or exhaust manifolds and become
damaged.
Fig. 9 Automatic Transmission Oil Cooler
1 ± CLAMPS
2 ± HOSES
Fig. 10 Accessory Drive Belts
1 ± GENERATOR BELT
2 ± AUTOMATIC BELT TENSIONER
3 ± POWER STEERING PUMP/A/C COMPRESSOR BELT
Fig. 11 Engine Block Heater
1 ± CORE PLUG
2 ± BLOCK HEATER
3 ± POWER CORD
7 - 6 COOLING SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

DIAGNOSIS AND TESTING
COOLING SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSE CORRECTION
TEMPERATURE GAUGE READS
LOW1. Has a Diagnostic Trouble Code
(DTC) been set indicating a stuck
open engine thermostat?1. Refer to On Board Diagnostic in
Group 25. Replace thermostat, if
necessary. If a (DTC) has not been
set, the problem may be with the
temperature gauge.
2. Is the temperature gauge (if
equipped) connected to the
temperature gauge coolant sensor
on the engine?2. Check the connector at the
engine coolant sensor. Refer to
Group 8E. Repair as necessary.
3. Is the temperature gauge (if
equipped) operating OK?3. Check Gauge operation. Refer to
Group 8E. Repair as necessary.
4. Coolant level low during cold
ambient temperature, accompanied
by poor heater performance.4. Check coolant level in the coolant
recovery/reserve container and the
radiator. Inspect the system for
leaks. Repair as necessary. Refer to
WARNINGS in this section before
removing pressure cap.
TEMPERATURE GAUGE READS
HIGH OR ENGINE COOLANT
WARNING LAMP ILLUMINATES.
COOLANT MAY OR MAY NOT BE
LOST FROM SYSTEM.1. Trailer being towed, a steep hill
being climbed, vehicle being
operated in slow moving traffic, or
engine idling during high ambient
(outside) temperatures with air
conditioning on. High altitudes
Could aggravate these conditions.1. This may be a temporary
condition and repair is not
necessary. Turn off the air
conditioning and drive the vehicle
without any of the previous
conditions. Observe the temperature
gauge the gauge should return to
the normal range. If the gauge does
not return to the normal range,
determine the cause of the
overheating and repair. Refer to
POSSIBLE CAUSES in this section.
2. Is temperature gauge (if
equipped) reading correctly?2. Check gauge. Refer to Group 8E.
Repair as necessary.
3. Is temperature warning lamp (if
equipped) illuminating
unnecessarily?3. Check warning lamp operation.
Refer to Group 8E. Repair as
necessary.
4. Coolant low in recovery/reserve
container and radiator?4. Check for coolant leaks and
repair as necessary. Refer to
Checking Cooling System for Leaks
in this section.
5. Pressure cap not installed tightly.
If cap is loose, boiling point of
coolant will be lowered. Also refer
to the following step 6.5. Tighten cap.
PLCOOLING SYSTEM 7 - 7

CONDITION POSSIBLE CAUSE CORRECTION
16. Electric cooling fan not
operating properly.16. Check electric fan operation and
repair as necessary.
17. Cylinder head gasket leaking. 17. Check cylinder head gasket for
leaks. Refer to testing cooling
system for leaks. For repairs, refer
to Group 9, Engine.
18. Heater core leaking. 18. Check heater core for leaks.
Refer to Group 24, Heating and Air
Conditioning and repair as
necessary.
TEMPERATURE GAUGE READING
IS INCONSISTENT (FLUCTUATES,
CYCLES OR IS ERRATIC)1. The gauge may cycle up and
down. This is due to the cycling of
the electric radiator fan.1. A normal condition. No correction
is necessary. If gauge cycling is
going into the hot zone, check
electric fan operation and repair as
necessary. Refer to procedure in
this section.
2. During cold weather operation
with the heater blower in the high
position, the gauge reading may
drop slightly.2. A normal condition. No correction
is necessary.
3, Temperature gauge or engine
mounted gauge sensor is defective
or shorted.3. Check operation of gauge and
repair as necessary. Refer to Group
8E, Instrument Panel and Gauges.
4. Gauge reading rises when
vehicle is brought to a stop after
heavy use (engine still running).4. A normal condition. No correction
is necessary. The gauge should
return to normal range after vehicle
is driven.
5. Gauge reading high after
restarting a warmed-up (hot)
engine.5. A normal condition. No correction
is necessary. The gauge should
return to normal range after a few
minutes of engine operation.
6. Coolant level low in radiator (air
will build up in the cooling system
causing the thermostat to open
late).6. Check and correct coolant leaks.
Refer to Testing Cooling System For
Leaks in the section.
7. Cylinder head gasket leaking
allowing exhaust gas to enter
cooling system. This will cause
thermostat to open late.7. (a) Check for cylinder head
gasket leaks with a commercially
available Block Leak Tester. Repair
as necessary.
(b) Check for coolant in the engine
oil. Inspect for white steam emitting
from exhaust system. Repair as
necessary.
8. Water pump impeller loose on
shaft.8. Check water pump and replace
as necessary. Refer to Water Pump
in this section.
9. Loose drive belt (water pump
slipping).9. Check drive belt and correct as
necessary.
PLCOOLING SYSTEM 7 - 9
DIAGNOSIS AND TESTING (Continued)

CONDITION POSSIBLE CAUSE CORRECTION
INADEQUATE HEATER
PERFORMANCE.1. Has a diagnostic trouble code
(DTC) been set?1. Refer to On-Board Diagnostic in
Group 25, Emission Control
Systems.
2. Coolant level low. 2. Refer to testing cooling system
for leaks in this section. Repair as
necessary.
3. Obstructions in heater hose
fittings at engine.3. Remove heater hoses at both
ends and check for obstructions.
Repair as necessary.
4. Heater hose kinked. 4. Locate kinked area and repair as
necessary.
5. Water pump is not pumping
coolant to heater core. When the
engine is fully warmed up, both
heater hoses should be hot to the
touch. The water pump drive belt
may be slipping causing poor water
pump operation.5. Refer to water pump in this
section. Repair as necessary.
HEAT ODOR 1. Various heat shields are used at
certain driveline components. One
or more of these shields may be
missing.1. Locate missing shields and
replace or repair as necessary.
2. Is temperature gauge reading
above the normal range?2. Refer to the previous
Temperature Gauge Reads High in
these Diagnostic Charts. Repair as
necessary.
3. Is cooling fan operating
correctly?3. Refer to Cooling System Fan in
this section for diagnosis. Repair as
necessary.
4. Has undercoating been applied
to any unnecessary component.4. Clean undercoating as necessary.
5. Engine may be running rich
causing the catalytic converter to
overheat.5. Refer to appropriate Powertrain
Diagnostic Procedures manual for
operation of the DRB scan tool.
Repair as necessary.
POOR DRIVEABILITY
(THERMOSTAT POSSIBLY STUCK
OPEN). GAUGE MAY BE READING
LOW1. For proper driveability, good
vehicle emissions and for
preventing build-up of engine oil
sludge, the thermostat must be
operating properly. Has a diagnostic
trouble code (DTC ) been set?1. Refer to On-Board Diagnostics in
Group 25, Emission Control
Systems. DTC's may also be check
using the DRB scan tool. Refer to
the proper Powertrain Diagnostic
Procedure manual for checking the
thermostat if necessary.
7 - 12 COOLING SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

ENGINE THERMOSTAT TESTING
The thermostat is operated by a wax filled con-
tainer (pellet) which is sealed. When heated coolant
reaches a predetermined temperature the wax pellet
expands enough to overcome the closing spring and
water pump pressure, which forces the valve to open.
Coolant leakage into the pellet will cause a thermo-
stat to fail open. Do not attempt to free up a thermo-
stat with a screwdriver.
The thermostat that opens too soon type failure
mode is included in the on-board diagnosis. Thecheck engine light will not be lit by an open too soon
condition. If it has failed open, a diagnostic trouble
code (DTC) will be set. Do not change a thermostat
for lack of heater performance or temperature gauge
position, unless a DTC is present. See Diagnosis for
other probable causes. Thermostat failing shut is the
normal long term mode of failure, and normally, only
on high mileage vehicles. The temperature gauge will
indicate this. Refer to Diagnosis in this section.
ACCESSORY DRIVE BELT DIAGNOSIS
CONDITION POSSIBLE CAUSE CORRECTION
BELT SLIPPAGE 1. Belt slipping because of
insufficient tension.1. Retension generator belt.
Replace the power steering belt's
automatic belt tensioner.
2. Belt excessively glazed or
hardened from heat and excessive
slippage.2. Replace belt.
3. Incorrect belt. 3. Replace belt.
4. Driven component bearing
failure.4. Replace faulty component.
5. Belt or pulley subjected to
substance (belt dressing, oil,
ethylene glycol) that has reduced
friction.5. Replace belt and clean pulleys.
BELT NOISE (OBJECTIONABLE
SQUEAL, SQUEAK, OR RUMBLE)1. Belt slippage. 1. Retension generator belt, replace
belt, or automatic belt tensioner.
2. Foreign material imbedded in
belt.2. Replace belt.
3. Non-uniform belt. 3. Replace belt.
4. Misaligned pulley(s). 4. Align accessories.
5. Non-uniform groove or eccentric
pulley.5. Replace pulley(s).
6. Bearing noise. 6. Locate and repair.
BELT ROLLED OVER IN GROOVE
OR BELT JUMPS OFF1. Broken cord in belt. 1. Replace belt.
2. Belt tension too loose, or too
tight.2. Retension generator belt.
Replace the power steering belt's
automatic belt tensioner.
3. Misaligned pulleys. 3. Align accessories.
4. Non-uniform grooves or eccentric
pulley.4. Replace pulley(s).
5. Foreign object(s) in grooves. 5. Remove foreign objects in
groove.
7 - 14 COOLING SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

the coolant to expand. Reattach the tester. If the nee-
dle on the dial fluctuates it indicates a combustion
leak, usually a head gasket leak.
WARNING: WITH THE PRESSURE TESTER IN
PLACE PRESSURE BUILDS UP QUICKLY. ANY
EXCESSIVE PRESSURE BUILD-UP DUE TO CON-
TINUOUS ENGINE OPERATION MUST BE
RELEASED TO A SAFE PRESSURE POINT. NEVER
PERMIT PRESSURE TO EXCEED 138 kPa (20 psi).
If the needle on the dial does not fluctuate, race
the engine a few times. If an abnormal amount of
coolant or steam is emitted from the tail pipe, it may
indicate a faulty head gasket, cracked engine block,
or cracked cylinder head.
There may be internal leaks, which can be deter-
mined by removing the oil dipstick. If water globules
appear intermixed with the oil, it indicates an inter-
nal leak in the engine. If there is an internal leak,
the engine must be disassembled for repair.
PRESSURE CAP TO FILLER NECK SEAL
PRESSURE RELIEF CHECK
The pressure cap upper gasket (seal) pressure
relief can be checked by removing the overflow hose
at the radiator filler neck nipple (Fig. 13). Attach the
radiator pressure tester to thefiller neck nipple,
and pump air into the system. The pressure cap
upper gasket should relieve pressure at 69-124 kPa
(10-18 psi), and hold pressure at 55 kPa (8 psi) min-
imum.
WARNING: THE WARNING WORDS DO NOT OPEN
HOT ON THE PRESSURE CAP IS A SAFETY PRE-
CAUTION. WHEN HOT, THE COOLING SYSTEM
BUILDS UP PRESSURE. TO PREVENT SCALDING
OR OTHER INJURY, THE PRESSURE CAP SHOULD
NOT BE REMOVED WHILE THE SYSTEM IS HOT
AND/OR UNDER PRESSURE.
There is no need to remove the pressure cap at any
timeexceptfor the following purposes:
²Check and adjust coolant freeze point
²Refill system with new coolant
²Conducting service procedures
²Checking for leaks
WARNING: IF VEHICLE HAS BEEN RUN RECENTLY,
WAIT 15 MINUTES BEFORE REMOVING CAP.
PLACE A SHOP TOWEL OVER THE CAP, AND WITH-
OUT PUSHING DOWN, ROTATE IT COUNTER-
CLOCKWISE TO THE FIRST STOP. ALLOW FLUIDSTO ESCAPE THROUGH THE OVERFLOW TUBE.
WHEN THE SYSTEM STOPS PUSHING COOLANT
AND STEAM INTO THE CRS TANK AND PRESSURE
DROPS, PUSH DOWN ON THE CAP AND REMOVE
IT COMPLETELY. SQUEEZING THE RADIATOR
INLET HOSE WITH A SHOP TOWEL (TO CHECK
PRESSURE) BEFORE AND AFTER TURNING TO
THE FIRST STOP IS RECOMMENDED.
PRESSURE TESTING COOLING SYSTEM
PRESSURE CAP
Dip the pressure cap in water; clean off any depos-
its on the vent valve or its seat, and apply the cap to
end of radiator pressure tester (Fig. 14). Working the
plunger, increase the pressure to 104 kPa (15 psi) on
the gauge. If the pressure cap fails to hold pressure
of at least 97 kPa (14 psi), replace the cap.
Fig. 13 Cooling System Pressure Cap
1 ± PRESSURE RATING
2 ± FILLER NECK SEAL
3 ± PRESSURE VALVE
4 ± VACUUM VENT VALVE (SHOWN IN SEALING POSITION)
7 - 16 COOLING SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

COOLANTÐADDING ADDITIONAL
NOTE: The radiator cap should not be removed.
When additional coolant is needed, it should be
added to the coolant recovery/reserve container (Fig.17). Use only 50/50 concentration of ethylene glycol
type antifreeze and water
COOLANT LEVELÐSERVICING
NOTE: The cooling system is closed and designed
to maintain coolant level to the top of the radiator.
When servicing requires a coolant level check in
the radiator, the engine must beoffandnotunder
pressure. Drain several ounces of coolant from the
radiator drain cock while observing the Coolant
Recovery Container. Coolant level in the container
should drop slightly. Then remove the radiator cap,
(Fig. 17). The radiator should be full to the top. If
not, and the coolant level in the recovery container is
at the ADD mark there is a air leak in the recovery
system. Check hose or hose connections to the recov-
ery container, radiator filler neck or the pressure cap
seal to the radiator filler neck for leaks.
Fig. 17 Coolant Recovery Container and Pressure Cap Locations
1 ± ENGINE OIL FILL
2 ± ENGINE COOLANT RECOVERY CONTAINER3 ± ENGINE OIL DIPSTICK
4 ± COOLING SYSTEM PRESSURE CAP
Fig. 16 Coolant Level
1 ± COOLANT RECOVERY CONTAINER
7 - 18 COOLING SYSTEMPL
SERVICE PROCEDURES (Continued)