1996 CHRYSLER VOYAGER cooling

THERMOSTAT OPERATION
2.5 VM DIESEL
The engine cooling thermostats are wax pellet
driven, reverse poppet choke type. They are designed
to provide the fastest warm up possible by prevent-
ing leakage through them and to guarantee a mini-
mum engine operating temperature (Fig. 10). The
thermostat has a hole to bleed off air in the cooling
system during engine warm up. The thermostat
begins to open at 80É C62É (176É F64É).
PRESSURE/VENT CAP
WARNING: Engine coolant can reach temperatures
of 200É fahrenheit or greater. If the cooling system
is opened with coolant at a high temperature, hot
coolant can be forced out of the system under high
pressures, causing personal injury. Allow system to
cool down prior to removing the pressure cap.
The pressure/vent cap is secured to the coolant
tank neck by a means of a cam lock system. This cap
releases excess pressure at some point within a
range of 90-117 kPa (13- 17 psi) for gasoline engines,
and 110±124 kPa (16±18 psi) for diesel engines. The
actual pressure relief point (in pounds) is labeled on
top of the cap (Fig. 11).
The cooling system will operate at pressures
slightly above atmospheric pressure. This results in a
higher coolant boiling point allowing increased radi-
ator cooling capacity. The cap (Fig. 11) contains a
spring-loaded pressure relief valve. This valve opens
when system pressure reaches approximately 103
kPa (15 psi).
When the engine is cooling down, vacuum is
formed within the cooling system. To prevent collapse
of the radiator and coolant hoses from this vacuum, a
vacuum valve is used within the cap. This valve pre-
vents excessive pressure differences from occurring
between the closed cooling system and the atmo-
sphere. If the vacuum valve is stuck shut, the radia-
tor and/or cooling system hoses will collapse on cool-
down.
Fig. 7 Water PumpÐ2.0L Gasoline Engine
Fig. 8 Water PumpÐ2.0L Gasoline Engine
Fig. 9 Water PumpÐ2.5L VM Diesel
Fig. 10 Thermostat and Housing Ð 2.5L VM Diesel
7 - 4 COOLING SYSTEMNS/GS
DESCRIPTION AND OPERATION (Continued)

NOTE: Do not use any type of tool when tighten-
ing the cap. Hand tighten only (approximately 5 N´m
or 44 in. lbs.) torque.
COOLANT PERFORMANCE
ETHYLENE-GLYCOL MIXTURES
The required ethylene-glycol (antifreeze) and water
mixture depends upon the climate and vehicle oper-
ating conditions. The recommended mixture of 50/50
ethylene-glycol and water will provide protection
against freezing to -37 deg. C (-35 deg. F). The anti-
freeze concentrationmust alwaysbe a minimum of
44 percent, year-round in all climates.If percentage
is lower than 44 percent, engine parts may be
eroded by cavitation, and cooling system com-
ponents may be severely damaged by corrosion.
Maximum protection against freezing is provided
with a 68 percent antifreeze concentration, which
prevents freezing down to -67.7 deg. C (-90 deg. F). A
higher percentage will freeze at a warmer tempera-
ture.100 Percent Ethylene-GlycolÐShould Not Be Used in
Chrysler Vehicles
Use of 100 percent ethylene-glycol will cause for-
mation of additive deposits in the system, as the cor-
rosion inhibitive additives in ethylene-glycol require
the presence of water to dissolve. The deposits act as
insulation, causing temperatures to rise to as high as
149 deg. C (300) deg. F). This temperature is hot
enough to melt plastic and soften solder. The
increased temperature can result in engine detona-
tion. In addition, 100 percent ethylene-glycol freezes
at 22 deg. C (-8 deg. F ).
Propylene-glycol FormulationsÐShould Not Be Used in
Chrysler Vehicles
Propylene-glycol formulations do not meet
Chrysler coolant specifications.It's overall effec-
tive temperature range is smaller than that of ethyl-
ene-glycol. The freeze point of 50/50 propylene-glycol
and water is -32 deg. C (-26 deg. F). 5 deg. C higher
than ethylene-glycol's freeze point. The boiling point
(protection against summer boil-over) of propylene-
glycol is 125 deg. C (257 deg.F)at96.5 kPa (14 psi),
compared to 128 deg. C (263 deg. F) for ethylene-gly-
col. Use of propylene-glycol can result in boil-over or
freeze-up in Chrysler vehicles, which are designed for
ethylene-glycol. Propylene glycol also has poorer heat
transfer characteristics than ethylene glycol. This
can increase cylinder head temperatures under cer-
tain conditions.
Propylene-glycol/Ethylene-glycol MixturesÐShould Not Be
Used in Chrysler Vehicles
Propylene-glycol/ethylene-glycol Mixtures can
cause the destabilization of various corrosion inhibi-
tors, causing damage to the various cooling system
components. Also, once ethylene-glycol and propy-
lene-glycol based coolants are mixed in the vehicle,
conventional methods of determining freeze point will
not be accurate. Both the refractive index and spe-
cific gravity differ between ethylene glycol and propy-
lene glycol.
CAUTION: Richer antifreeze mixtures cannot be
measured with normal field equipment and can
cause problems associated with 100 percent ethyl-
ene-glycol.
BELT TENSION
Correct accessory drive belt tension is required to
be sure of optimum performance of belt driven engine
accessories. If specified tension is not maintained,
belt slippage may cause; engine overheating, lack of
power steering assist, loss of air conditioning capac-
ity, reduced generator output rate and greatly
reduced belt life.
Fig. 11 Coolant Tank Pressure/Vent Cap
NS/GSCOOLING SYSTEM 7 - 5
DESCRIPTION AND OPERATION (Continued)

Initial belt adjustment is done with a adjustable
tensioner pulley. After the initial adjustment is per-
formed, an automatic belt tensioner is used to main-
tain correct belt tension at all times. Do not attempt
to check belt tension with a belt tension gauge on
vehicles equipped with an automatic belt tensioner.
Refer to Automatic Belt Tensioner in this group.
AUTOMATIC BELT TENSIONER
Drive belt tension is controlled by a spring loaded
automatic belt tensioner located below and to the
front of the engine oil filter (Fig. 12). This tensioner
is connected to a pivot bracket and a pulley (Fig. 12).
The pivot bracket rotates on a pivot pin attached to
the engine. Special machined washers with rubber
o-rings (Fig. 12) are used at each side of the pivot
bracket to help keep dirt and water away from the
pivot pin.
If a defective belt tensioner is suspected, a check of
this pivot bracket and pivot pin should be made. Cor-
rosion may have formed at the pin and may cause
the pivot bracket to stick. Belt slippage will result.
WARNING: BECAUSE OF HIGH SPRING PRES-
SURE, DO NOT ATTEMPT TO DISASSEMBLE THE
AUTOMATIC BELT TENSIONER. UNIT IS SERVICED
AS AN ASSEMBLY.
THERMOSTAT
DIAGNOSIS
Diesel engines, due to their inherent efficiency are
slower to warm up than gasoline powered engines,
and will operate at lower temperatures when the
vehicle is unloaded. Because of this, lower tempera-
ture gauge readings for diesel versus gasoline
engines may, at times be normal.
Typically, complaints of low engine coolant temper-
ature are observed as low heater output when com-
bined with cool or cold outside temperatures.
To help promote faster engine warm-up, an electric
engine block heater must be used with cool or cold
outside temperatures. This will help keep the engine
coolant warm when the vehicle is parked. Use the
block heater if the outside temperature is below 4ÉC
(40ÉF).Do not use the block heater if the out-
side temperature is above 4ÉC (40ÉF).
TESTING
NOTE: The DRB scan tool shoud be used to moni-
tor engine coolant temperature on the diesel
engine. Refer to the 1998 GS Powertrain Diagnostic
Manual for thermostat diagnosis procedure.
Fig. 12 Automatic Belt Tensioner Assembly
7 - 6 COOLING SYSTEMNS/GS
DESCRIPTION AND OPERATION (Continued)

SERVICE PROCEDURES
ADDING ADDITIONAL COOLANT
2.5L VM DIESEL
Do not remove coolant bottle pressure cap when
the engine is hot. Remove pressure cap and fill cool-
ant bottle between Min and Max lines inside filler
neck. Use only 50/50 mix of ethylene glycol type anti-
freeze and water (Fig. 13). Squeezing radiator hoses
may help purge air from the cooling system.
DRAINING COOLING SYSTEM
2.0L GASOLINE
To drain cooling system move temperature selector
for heater to full heat with engine running.Without
removing radiator pressure cap and with sys-
tem not under pressure,Shut engine off and open
draincock. The coolant reserve tank should empty
first, then remove radiator pressure cap and let the
radiator drain (if not, see Testing Cooling System for
leaks).
2.5L VM DIESEL
The cooling system does not have a radiator
mounted pressure cap. Instead the pressure cap is
mounted on the coolant pressure bottle (Fig. 14).
(1) Shut off engine.
(2) Remove radiator pressure cap.
(3) Open draincock and allow coolant to drain.
REFILLING COOLING SYSTEM
2.0L GASOLINE
Refer to the gasoline engine cooling system infor-
mation in this manual. Cooling system capacity is 6.0
liters (6.34 qts.) which includes the heater and cool-
ant recovery tank.
2.5L VM DIESEL
First clean system to remove old glycol, see Cooling
System Cleaning.
(1) Disconnect upper radiator hose at thermostat
housing.
(2) Remove pressure cap from coolant expansion
tank.
(3) Fill cooling system through upper radiator hose
until coolant starts to leak out at the thermostat
housing. Reconnect hose and re-install clamp.
(4) Fill expansion tank to top of bottle. Run engine
at idle without pressure cap installed for 5 minutes.
Squeeze upper radiator hose several times.
(5) Shut off engine. Top off coolant and install
pressure cap.
(6) Inspect system for leaks.
REMOVAL AND INSTALLATION
WATER PUMP Ð 2.0L GASOLINE
REMOVAL
(1) Remove accessory drive belts and power steer-
ing pump.
(2) Drain cooling system.
Fig. 13 Coolant Pressure BottleÐ2.5L VM Diesel
Fig. 14 Pressure Cap and BottleÐVM Diesel
NS/GSCOOLING SYSTEM 7 - 7

(3) Remove power steering pump bracket bolts and
set pump and bracket assembly aside. Power steering
lines do not need to be disconnected.
(4) Remove timing belt.
(5) Remove inner timing belt cover.
(6) Remove water pump attaching screws to engine
(Fig. 15).
INSTALLATION
(1) Install new O-ring gasket in water pump body
O-ring groove (Fig. 16). Use small dabs of Mopar Sil-
icone Rubber Adhesive Sealant around the water
pump body to secure O-ring in place during installa-
tion.
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 and cause a coolant leak.
(2) 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.
(3) Rotate pump by hand to check for freedom of
movement.
(4) Install inner timing belt cover.
(5) Install timing belt.
(6) Fill cooling system. SeeFilling Cooling Sys-
tem.
(7) Install power steering pump and accessory
drive belts.
WATER PUMP Ð 2.5L VM DIESEL
REMOVAL
(1) Drain cooling system. Refer to Draining Cool-
ing System in this Group.
(2) Remove the right inner splash shield (Fig. 17).
(3) Loosen the water pump pulley attaching bolts
(Fig. 18) before the accessory drive belt is removed.
(4) Loosen water pump accessory drive belts (Fig.
19). Remove water pump pulley.(5) Remove water pump attaching bolts and
remove pump.
INSTALLATION
(1) Install a new water pump to housing O-ring
gasket. Install pump and tighten the attaching bolts
to 22.6 N´m (205 in. lbs.)
Fig. 15 Water Pump Ð 2.0L Gasoline
Fig. 16 Water Pump Body Ð 2.0L Gasoline
Fig. 17 Right Side Splash Shield
Fig. 18 Water Pump and Pulley Ð 2.5 L VM Diesel
7 - 8 COOLING SYSTEMNS/GS
REMOVAL AND INSTALLATION (Continued)

(2) Install water pump pulley.
(3) Install drive belt, Refer to Accessory Drive
Belts, this Group. Tighten water pump pulley attach-
ing bolts to 27.5 N´m (240 in. lbs.)
(4) Install right inner splash shield.
(5) Refill cooling system. Refer to Refilling Cooling
System in this Group.
ENGINE THERMOSTATÐ 2.0L GASOLINE
REMOVAL
(1) Drain cooling system to the thermostat level or
below.
(2) Remove coolant recovery system (CRS) hose
and thermostat/engine outlet connector bolts.
(3) Remove thermostat and seal, and clean sealing
surfaces.
INSTALLATION
(1) Place the new thermostat assembly into the
thermostat housing/outlet connector. Align air bleed
vent with notch in cylinder head.
(2) Install thermostat housing/outlet connector
onto cylinder head and tighten bolts to 12.5 N´m (110
in. lbs.). Connect the upper radiator hose.
(3) Refill cooling system (seeRefilling System).
THERMOSTAT Ð 2.5L VM DIESEL
REMOVAL
(1) Drain cooling system down below the thermo-
stat level. Refer to Draining Cooling System in this
section.(2) Remove radiator hose at thermostat cover.
(3) Remove thermostat cover bolts (Fig. 20).
(4) Remove Thermostat.
INSTALLATION
(1) Remove old gasket material from thermostat
housing and cover.
(2) Install new thermostat gasket.
(3) Install thermostat and tighten cover bolts to
10.8 N´m (96 in. lbs.).
(4) Install radiator hose.
(5) Refill cooling system. Refer to Refilling Cooling
System in this section.
RADIATOR Ð 2.5L VM DIESEL
REMOVAL
(1) Disconnect battery.
(2) Remove power steering reservoir attaching
bolts, and reposition reservoir.
(3) Remove radiator closure panel crossmember
(Fig. 21).
(4) Remove air cleaner housing and intake hose.
(5) Unplug fan module 4 pin wiring connector.
(6) Drain cooling system. Refer to Draining cooling
system in this section for procedure.
(7) Remove upper and lower Radiator Hoses.
(8) Remove radiator attaching bolts.
(9) Loosen A/C receiver/dryer lower bolt.
(10) Remove Radiator.
(11) Remove fan module from radiator.
Fig. 19 Water Pump Drive BeltÐ 2.5 L VM Diesel
Fig. 20 Thermostat and Housing Ð 2.5L VM Diesel
NS/GSCOOLING SYSTEM 7 - 9
REMOVAL AND INSTALLATION (Continued)

INSTALLATION
(1) Install fan module on radiator.
(2) Install radiator.
(3) Tighten receiver/dryer lower bolt.
(4) Install radiator attaching bolts.
(5) Install lower and upper radiator hoses.
(6) Connect fan module.
(7) Install air cleaner housing and intake hose.
(8) Install radiator closure panel crossmember.
(9) Install power steering reservoir attaching bolts.
(10) Refill cooling system. Refer to Refilling cooling
system in this section for procedure.
(11) Connect battery.
WATER PUMP BELT Ð 2.5L VM DIESEL
REMOVAL
(1) Remove generator/power steering belt. Refer to
procedure in this section.
(2) Raise vehicle on hoist.
(3) Remove right side splash shield (Fig. 22).
(4) Loosen belt tensioner bracket bolts (Fig. 23).(5) Loosen adjuster lock nut.
(6) Loosen adjusting bolt, and remove belt.
INSTALLATION
(1) Install water pump belt.
(2) Turn adjusting bolt clockwise to tighten belt.
(3) Tighten lock nut.
(4) Tighten belt tensioner bracket bolts
(5) Lower vehicle.
(6) Install generator/power steering belt. Refer to
procedure in this section.
GENERATOR/POWER STEERING BELT Ð 2.5L VM
DIESEL
REMOVAL
(1) Loosen generator pivot bolt (Fig. 24).
(2) Loosen adjusting bracket bolt.
(3) Loosen adjusting nut.
(4) Remove generator/power steering belt.
INSTALLATION
(1) Install generator/power steering belt.
(2) Tighten adjusting nut.
(3) Tighten adjusting bracket bolt.
(4) Tighten generator pivot bolt.
CLEANING AND INSPECTION
WATER PUMP
Replace the water pump if it has any of the follow-
ing defects.
(1) Damage or cracks on the pump body.
Fig. 21 Radiator Closure Panel Crossmember
Fig. 22 Right Side Splash Shield
Fig. 23 Water Pump Belt Removal Ð 2.5L VM Diesel
7 - 10 COOLING SYSTEMNS/GS
REMOVAL AND INSTALLATION (Continued)

(2) Coolant leaks; if the seal is leaking, this will be
evident by traces of thick deposits of greenish-brown
dried glycol running down the pump body and com-
ponents below. A thin black stain below pump weep
hole is considered normal operation.
(3) Impeller rubs inside of the cylinder block 2.0L
engine. Impeller rubs inside of the water pump hous-
ing 2.5L VM diesel engine.
(4) Excessively loose or rough turning bearing.
NOTE: It is normal for the water pump to weep a
small amount of coolant from the weep hole (black
stain on water pump body). Do not replace the
water pump if this condition exists. Replace the
water pump if a heavy deposit or a steady flow of
green/brown engine coolant is evident on water
pump body from the weep hole (shaft seal failure).
Be sure to perform a thorough analysis before
replacing water pump.
ADJUSTMENTS
BELT TENSION GAUGE METHOD
Use belt tensioning Special Tool Kit C-4162 for:
CAUTION: The Burroughs gauge for the Poly-V
belt is not to be used on the V-belt. These gauges
are not interchangeable.
²For conventional V-belts affix the Burroughs
gauge (Special Tool C-4162) to the belt. Adjust the
belt tension for New or Used belt as prescribed in the
Belt Tension Chart. For a Poly-V belt affix the Poly-V
Burroughs gauge to the belt and then apply specified
tension to the belt as prescribed in the Belt Tension
Chart
Adjust the belt tension for aNeworUsedbelt as
prescribed in the Belt Tension Chart.
BELT TENSION CHART
Fig. 24 Generator/Power Steering Removal ± 2.5L
VM Diesel
ACCESSORY DRIVE
BELTGAUGE
2.0L GASOLINE ENGINE
GENERATOR AND AIR
CONDITIONINGNEW 667644 N (150
610 LBS).
USED 556 N (125 LBS.)
POWER STEERING NEW 578644 N (130
610 LBS).
USED 489 N (110 LBS).
2.5L VM DIESEL
WATER PUMP NEW N/A LBS.
USED N/A LBS.
GENERATOR /AIR
CONDITIONING/
POWER STEERINGNEW 667644 N (150
610 LBS).
USED 556 N (125 LBS).
NS/GSCOOLING SYSTEM 7 - 11
CLEANING AND INSPECTION (Continued)