2000 DODGE NEON Service Repair Manual

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)

WATER PUMP DIAGNOSIS
A quick flow test to tell whether or not the pump is
working is to see if the heater warms properly. A
defective pump will not be able to circulate heated
coolant through the long heater hose.
Another flow test to help determine pump opera-
tion:
WARNING: DO NOT remove radiator cap if the cool-
ing system is hot or under pressure.
(1) Remove cooling system pressure cap.
(2) Remove a small amount of coolant from the
system.
(3) Start the engine and warm up until thermostat
opens.
(4) With the thermostat open and coolant level low,
visually inspect for coolant flow. If flow is present,
the water pump is pumping coolant through the sys-
tem.
COOLING SYSTEM FLOW CHECK
To determine whether coolant is flowing through
the cooling system, use the following procedures:
(1) If engine is cold, idle engine until normal oper-
ating temperature is reached. Then feel the upper
radiator hose. If it is hot, coolant is circulating.
WARNING: DO NOT REMOVE THE COOLING SYS-
TEM PRESSURE CAP WITH THE SYSTEM HOT AND
UNDER PRESSURE BECAUSE SERIOUS BURNS
FROM COOLANT CAN OCCUR.
(2) Remove pressure cap when engine is cold,
remove small amount of coolant Idle engine until
thermostat opens, you should observe coolant flow
while looking down the filler neck. Once flow is
detected install the pressure cap.
ELECTRIC FAN MOTOR TEST
Refer to Powertrain Diagnostic Manual for proce-
dure.
COOLANT CONCENTRATION TESTING
Coolant concentration should be checked when any
additional coolant was added to system or after a
coolant drain, flush and refill. The coolant mixture
offers optimum engine cooling and protection against
corrosion when mixed to a freeze point of -37ÉC
(-34ÉF) to -59ÉC (-50ÉF). The use of a hydrometer or a
refractometer can be used to test coolant concentra-
tion.
A hydrometer will test the amount of glycol in a
mixture by measuring the specific gravity of the mix-
ture. The higher the concentration of ethylene glycol,
the larger the number of balls that will float, andhigher the freeze protection (up to a maximum of
70% by volume glycol).
A refractometer will test the amount of glycol in a
coolant mixture by measuring the amount a beam of
light bends as it passes through the fluid.
Some coolant manufactures use other types of gly-
cols into their coolant formulations. Propylene glycol
is the most common new coolant. However, propylene
glycol based coolants do not provide the same freez-
ing protection and corrosion protection and is only
recommended for limited usage. Refer to appropriate
Technical Service Bulletin(s) regarding use of propy-
lene glycol based coolants.
CAUTION: Do not mix types of coolantÐcorrosion
protection will be severely reduced.
Because ethylene glycol and propylene glycol do
not have the same specific gravities, the use of a
hydrometer will be inaccurate. Therefore, Special
Tool 8286 refractometer, is recommended when test-
ing either ethylene or propylene glycol coolants.
TESTING COOLING SYSTEM FOR LEAKS
The system should be full. With the engine not
running, wipe the filler neck sealing seat clean.
Attach a radiator pressure tester to the filler neck,
as shown in (Fig. 12) and apply 104 kPa (15 psi)
pressure. If the pressure drops more than 2 psi in 2
minutes, inspect the system for external leaks.
Move all hoses at the radiator and heater while
system is pressurize at 15 psi, since some leaks occur
due to engine rock while driving.
If there are no external leaks after the gauge dial
shows a drop in pressure, detach the tester. Start the
engine, and run the engine to normal operating tem-
perature in order to open the thermostat and allow
Fig. 12 Pressure Testing Cooling SystemÐTypical
1 ± PRESSURE TESTER
PLCOOLING SYSTEM 7 - 15
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)

CAUTION: The radiator pressure tester is very sen-
sitive to small air leaks that will not cause cooling
system problems. A pressure cap that does not
have a history of coolant loss should not be
replaced just because it leaks slowly when tested
with this tool. Add water to the tool. Turn the tool
upside down, and recheck the pressure cap to con-
firm that the cap is faulty.
If the pressure cap tests properly while posi-
tioned the on radiator pressure tester, but will not
hold pressure or vacuum when positioned on the
filler neck, inspect the filler neck and cap top gas-
ket for irregularities that may prevent the cap from
sealing properly.
LOW COOLANT LEVEL AERATION
²Will cause corrosion in the system.
²High reading shown on the temperature gauge.
²Air in the coolant will also cause loss of flow
through the heater.
²Exhaust gas leaks into the coolant can also
cause the above problems.
DEAERATION
Air can only be removed from the system by gath-
ering under the pressure cap. On the next heat up it
will be pushed past the pressure cap into the coolant
recovery container by thermal expansion of the cool-
ant. It then escapes to the atmosphere in the coolant
recovery container and is replaced with coolant on
cool down.
TEMPERATURE GAUGE INDICATION
At idle the temperature gauge could rise slowly to
about 1/2 gauge travel. The fan will come on and the
gauge could drop to about 1/3 gauge travel, this is
normal.
ENGINE BLOCK HEATER
If heater unit does not operate (Fig. 15), possible
causes can be either the power cord or the heater ele-
ment. Test the power cord for continuity with a 110-
volt voltmeter or 110-volt test light. Test heater
element continuity with an ohmmeter or a 12-volt
test light.
CAUTION: To prevent damage, the power cord
must be secured in its retainer clips and away from
any components that may cause abrasion or dam-
age, such as linkages, exhaust components, etc.
SERVICE PROCEDURES
COOLANT LEVEL CHECKÐROUTINE
NOTE: Do not remove radiator cap for routine cool-
ant level inspections.
The coolant recovery/reserve system provides a
quick visual method for determining the coolant level
without removing the radiator cap. Simply observe,
with the engine idling and warmed up to normal
operating temperature, that the level of the coolant
in the recovery/reserve container (Fig. 16) is between
the FULL HOT and ADD marks.
Fig. 14 Pressure Testing Radiator Cap
1 ± PRESSURE CAP
2 ± PRESSURE TESTER
Fig. 15 Engine Block Heater
1 ± CORE PLUG
2 ± BLOCK HEATER
3 ± POWER CORD
PLCOOLING SYSTEM 7 - 17
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)

COOLING SYSTEMÐDRAINING
NOTE: Drain, flush, and fill the cooling system at
the mileage or time intervals specified in Group 0,
Lubrication and Maintenance. If the solution is dirty,
rusty, or contains a considerable amount of sedi-
ment; clean and flush with a reliable cooling system
cleaner. Care should be taken in disposing of the
used engine coolant from your vehicle. Check gov-
ernmental regulations for disposal of used engine
coolant.
Without removing radiator pressure cap and
with system not under pressure:
(1) Shut engine off and turn draincock counter-
clockwise to open (Fig. 18).
(2) The coolant reserve tank should empty first,
then remove the pressure cap. (if not, Refer to Test-
ing Cooling System for leaks).
COOLING SYSTEMÐREFILLING
First clean system to remove old glycol, see Cooling
System Cleaning.
Fill system with 50/50 glycol/water mix. Use anti-
freeze described in Coolant section.
Continue filling system until full, this provides bet-
ter heater performance.Be careful not to spill
coolant on drive belts or the generator.
Fill coolant reserve/recovery system to at least the
FULL HOT mark with 50/50 solution. It may be nec-
essary to add coolant to the reserve/recovery con-
tainer after three or four warm-up/cool down cycles
to maintain coolant level between the FULL HOT
and ADD marks; if any trapped air was removed
from the system.
REMOVAL AND INSTALLATION
WATER PUMP
REMOVAL
(1) Raise vehicle on a hoist. Remove right inner
splash shield.
(2) Remove accessory drive belts. Refer to proce-
dure in this section.
(3) Drain cooling system. Refer to Cooling System
Draining in this section.
(4) Remove power steering pump attaching bolts
and set pump and assembly aside. Power steering
lines do not need to be disconnected.
(5) Remove upper and lower torque isolator struts.
(6) Support engine from the bottom and remove
right engine mount attaching bolt.
(7) Remove right engine mount bracket.
(8) Remove timing belt and timing belt tensioner.
Refer to Group 9, Engine for procedures.
(9) Remove camshaft sprocket and rear timing belt
cover. Refer to Group 9, Engine for procedures.
(10) Remove water pump attaching screws to
engine and remove pump (Fig. 19).
INSTALLATION
(1) Apply MopartDielectric Grease to O-ring
before installation.
(2) Install new O-ring gasket in water pump body
O-ring groove (Fig. 20).
CAUTION: Make sure O-ring gasket is properly
seated in water pump groove before tightening
screws. An improperly located O-ring may cause
damage to the O-ring, resulting in a coolant leak.
(3) Assemble pump body to block and tighten
screws to 12 N´m (105 in. lbs.). Pressurize cooling
system to 15 psi with pressure tester and check
water pump shaft seal and O-ring for leaks.
Fig. 18 Cooling System Drain Cock Location
1 ± DRAIN COCKFig. 19 Water Pump
1 ± CYLINDER BLOCK
2 ± PUMP BODY
PLCOOLING SYSTEM 7 - 19
SERVICE PROCEDURES (Continued)

(4) Rotate pump by hand to check for freedom of
movement.
(5) Install rear timing belt cover and camshaft
sprocket.
(6) Install timing belt tensioner and timing belt.
Refer to Group 9, Engine for procedure.
(7) Install right engine mount bracket. Refer to
Group 9, Engine for procedure.
(8) Install upper and lower torque isolator struts.
Refer to Group 9, Engine for procedure.
(9) Fill cooling system. Refer to procedures in this
section.
(10) Install accessory drive belts. Refer to proce-
dure in this section.
(11) Perform camshaft and crankshaft timing
relearn procedure as follows:
²Connect the DRB scan tool to the data link
(diagnostic) connector. This connector is located in
the passenger compartment; at the lower edge of
instrument panel; near the steering column.
²Turn the ignition switch on and access the ªmis-
cellaneousº screen.
²Select ªre-learn cam/crankº option and follow
directions on DRB screen.
WATER PUMP INLET TUBE
The inlet tube connects the water pump to the
radiator and heater core. This tube is sealed by an
O-ring and held in place by fasteners to the block.
REMOVAL
CAUTION: Do not use any sharp tools to remove
hoses from inlet tube. This may cause the tube to
leak.
(1) Drain cooling system. Refer to procedure in
this section.
(2) Remove upper radiator hose to access the hose
connections at the inlet tube.(3) Remove intake manifold. Refer to Group 9,
Engine for procedure.
(4) Remove lower radiator hose and heater hose
from the inlet tube.
(5) Remove lower intake manifold support bracket.
(6) Remove the inlet tube to the block fasteners.
(7) Rotate tube while removing the tube from the
engine block (Fig. 21).
INSTALLATION
(1) Inspect the O-ring for damage before installing
the tube into the cylinder block (Fig. 21). Replace
O-ring as necessary.
(2) Lubricate O-ring with MopartDielectric
Grease and install inlet tube into the cylinder block
opening.
(3) Install inlet tube fasteners and tighten fasten-
ers to 12 N´m (105 in. lbs.).
(4) Install intake manifold lower support bracket
fasteners and tighten to 12 N´m (105 in. lbs.).
(5) Connect lower radiator hose and heater hose to
inlet tube.
(6) Install intake manifold. Refer to Group 9,
Engine for procedure.
(7) Install upper radiator hose.
(8) Fill cooling system. Refer to procedure in this
section.
(9) Pressure system to 104 kPa (15 psi) to check
for leaks.
ENGINE THERMOSTAT
REMOVAL
(1) Drain cooling system to the thermostat level or
below.
(2) Remove coolant recovery/reserve system hose
and upper radiator hose.
Fig. 20 Water Pump Body
1 ± IMPELLER
2 ± PUMP BODY
3 ± O-RING
Fig. 21 Water Pump Inlet Tube
1 ± O-RING
2 ± WATER PUMP INLET TUBE
FRONT
7 - 20 COOLING SYSTEMPL
REMOVAL AND INSTALLATION (Continued)

(3) Remove thermostat/engine outlet connector
bolts (Fig. 22).
(4) Remove thermostat and O-ring assembly.
INSTALLATION
(1) Clean all sealing surfaces.
(2) Place the new thermostat assembly into the
thermostat housing/outlet connector. Align vent with
notch in cylinder head.
(3) Install thermostat housing/outlet connector
onto cylinder head and tighten bolts to 12.5 N´m (110
in. lbs.).
(4) Install upper radiator hose.
(5) Connect the coolant recovery/reserve system
hose.
(6) Refill cooling system. Refer to procedure in this
section.
RADIATOR
REMOVAL
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK PLUG OR THE RADIATOR DRAINCOCK
WITH THE SYSTEM HOT AND UNDER PRESSURE
BECAUSE SERIOUS BURNS FROM COOLANT CAN
OCCUR.
(1) Disconnect negative cable from battery.
(2) Drain cooling system. Refer to procedure in
this section.
(3) Remove upper radiator hose from the radiator.
(4) Disconnect and cap automatic transmission
hoses, if equipped.(5) Disconnect cooling fan motor electrical connec-
tor.
(6) Remove cooling fan module retaining screws,
located on the top of the shroud (Fig. 23). Lift shroud
up and out of bottom shroud attachment clips sepa-
rating shroud from radiator.
(7) Remove the lower radiator hose.
(8) Remove upper radiator isolator bracket mount-
ing screws (Fig. 24). Disconnect the engine block
heater wire, if equipped.
(9) Remove the air conditioning condenser attach-
ing screws located at the front of the radiator, if
equipped (Fig. 25), then lean condenser forward.
NOTE: It is not necessary to discharge the air con-
ditioning system to remove the radiator.
Fig. 22 Thermostat/Engine Outlet Connector
1 ± PRESSURE CAP
2 ± THERMOSTAT HOUSING/ENGINE OUTLET CONNECTOR
3 ± THERMOSTAT
4 ± O-RING
5 ± VENT FACING UP
Fig. 23 Fan Module Mounting
1 ± SCREWS
2 ± LOWER MOUNTS
3 ± FAN MOTOR ELECTRICAL CONNECTOR
Fig. 24 Radiator Mounting
1 ± UPPER RADIATOR HOSE
2 ± UPPER RADIATOR MOUNTS
PLCOOLING SYSTEM 7 - 21
REMOVAL AND INSTALLATION (Continued)