1998 ISUZU TROOPER engine

Full hot switch Ceramic heater Heater unit
HEATING AND VENTILATION 1A Ð 5
CERAMIC HEATER
When the fan control knob (fan switch) turns on with the temperature control knob set to ÒFULL HOTÓ (full
hot switch ÒONÓ), the ceramic heater in the heater unit gets hot, thus causing the heater blow temperature
of diesel vehicle to get high to improve the heating performance (Since the engine coolant temperature of
diesel vehicle is low, its blow temperature is also low.).
Glow plug
Full hot switch
Fan switch
Thermo switch
Less than 80¡C (177.8¡F)
CERAMIC HEATER
ÒONÓCERAMIC HEATER
ÒOFFÓ
OFF
ON
OFF
OFF
OFF
ON
ON
ON
This illustration is based on RHD

HEATING AND VENTILATION 1A Ð 7
INSTALLATION
To install, follow the removal steps in the reverse order,
noting the following points:
1. When handling the ECM and the control unit, be
careful not to make any improper connection of the
connectors.
2. Adjust control lever assembly cables.
Refer to ÒCONTROL LEVER ASSEMBLYÓ installation
steps in this section.
3. When installing the heater unit, defroster nozzle and
center vent duct, be sure that proper seal is made,
without any gap between then.
REMOVAL
Preparation:
·Disconnect the battery ground cable
·Drain engine coolant
·Discharge and recover refrigerant (W/A/C)
(Refer to Section 1B ÒREFRIGERANT RECOVERYÓ)
1. Instrument Panel Assembly
Refer to Section 10 ÒBODYÓ for INSTRUMENT PANEL
ASSEMBLY removal procedure.
2. Water Hose
Disconnect water hoses at heater unit.
3. Resistor Connector
4. Duct
4a. Evaporator Assembly
Refer to Section 1B ÒAIR CONDITIONINGÓ for
Evaporator Assembly removal procedure.
5. Instrument panel center bracket
6. Rear Heater Duct
7. Heater Unit
8. Lap vent nozzle
9. Center ventilation lower duct

HEATING AND VENTILATION 1A Ð 9
REMOVAL
Preparation:
·Disconnect the battery ground cable
·Drain engine coolant
1. Heater Unit
Refer to ÒHEATER UNITÓ removal procedure in this
section.
2. Duct
3. Case (Mode Control)
Do not remove link unit at this step.
4. Case (Temperature Control)
Separate two halves of core case.
Heater core
5. Heater Core
Heater core
6. Mode Door
Pull out the mode door while raising up the catch of
the door lever.
INSTALLATION
To install, follow the removal steps in the reverse order,
noting the following point:
1. Check that each mode door operates properly.

HEATING AND VENTILATION 1A Ð 11
REMOVAL
Preparation:
·Disconnect the battery ground cable
·Drain engine coolant
1. Heater Unit
Refer to ÒHEATER UNITÓ removal procedure in this
section.
2. Case (Mode Control)
Remove the case (Mode control) from heater unit.
3. Washer and Mode Main Lever
4. Rod
5. Mode Sub-Lever
Press the tab of the sub-lever inward, and take out the
sub-lever.
6. Door Lever
Pull out the door lever while raising up the catch of
the door lever.
INSTALLATION
To install, follow the removal steps in the reverse order,
noting the following points:
1. Apply grease to mode sub-lever and to the abrasive
surface of the heater unit.
2. After installing the link unit, check to see if the link
unit operates correctly.

HEATING AND VENTILATION 1A Ð 13
REMOVAL
Preparation:
·Disconnect the battery ground cable
·Drain engine coolant
1. Heater Unit
Refer to ÒHEATER UNITÓ removal procedure in this
section.
2. Case (Temperature Control)
Remove the case (Temperature control) from the
heater unit.
3. Rod
4. Sub-Lever
5. Door Lever
Pull out the door lever while raising up the catch of
the door lever.
6. Clip
INSTALLATION
To install, follow the removal steps in the reverse order,
noting the following points:
1. Apply grease to sub-lever and to the abrasive surface
of the heater unit.
2. After installing the link unit, check to see if the link
unit operates correctly.

AIR CONDITIONING 1B Ð 3
AIR CONDITIONING REFRIGERANT CYCLE CONSTRUCTION




 

 













 

 
 
 
 

 
 


 












 

 
 
 
 
 
 





1514
11
12
13
1610
177
34
5
2
18
96
13 Side vent
Lap ventOutside air
EngineSide vent
Cooling air
High pressure, high temperature gas
High pressure, high temperature
mixture of gas and liquid
Low pressure, low temperature
mixture of liquid and gas
Low pressure, low temperature gas High pressure, medium temperature liquidSide defrost Side defrostDefrost Center vent
GENERAL DESCRIPTION
1. Compressor
2. Magnetic clutch
3. Receiver/Drier
4. Dual pressure switch
5. Condenser
6. Evaporator assembly
7. Expansion valve
8. Temperature sensor
9. Evaporator core10. Blower motor
11. Heater unit
12. Heater core
13. Temp. control door (Air mix door)
14. Mode (DEF) control door
15. Mode (VENT) control door
16. Mode (HEAT) control door
17. Electronic thermostat

1B Ð 4 AIR CONDITIONING
The refrigeration cycle includes the following four
processes as the refrigerant changes repeatedly
from liquid to gas and back to liquid while
circulating.
EVAPORATION
The refrigerant is changed from a liquid to a gas
inside the evaporator. The refrigerant mist that
enters the evaporator vaporizes readily. The liquid
refrigerant removes the required quantity of heat
(latent heat of vaporization) from the air around the
evaporator core cooling fins and rapidly vaporizes.
Removing the heat cools the air, which is then
radiated from the fins and lowers the temperature
of the air inside the vehicle.
The refrigerant liquid sent from the expansion valve
and the vaporized refrigerant gas are both present
inside the evaporator and the liquid is converted to
gas.
With this change from liquid to gas, the pressure
inside the evaporator must be kept low enough for
vaporization to occur at a lower temperature.
Because of that, the vaporized refrigerant is sucked
into the compressor.
COMPRESSION
The refrigerant is compressed by the compressor
until it is easily liquefied at normal temperature.
The vaporized refrigerant in the evaporator is
sucked into the compressor. This action maintains
the refrigerant inside the evaporator at a low
pressure so that it can easily vaporize, even at low
temperatures close to 0¡C (32¡F).
Also, the refrigerant sucked into the compressor is
compressed inside the cylinder to increase the
pressure and temperature to values such that the
refrigerant can easily liquefy at normal ambient
temperatures.
CONDENSATION
The refrigerant inside the condenser is cooled by
the outside air and changes from gas to liquid.
The high temperature, high pressure gas coming
from the compressor is cooled and liquefied by the
condenser with outside air and accumulated in the
receiver/drier. The heat radiated to the outside air
by the high temperature, high pressure gas in the
compressor is called heat of condensation. This is
the total quantity of heat (heat of vaporization) the
refrigerant removes from the vehicle interior via the
evaporator and the work (calculated as the quantity
of heat) performed for compression.
EXPANSION
The expansion valve lowers the pressure of the
refrigerant liquid so that it can easily vaporize.
The process of lowering the pressure to encourage
vaporization before the liquefied refrigerant is sent
to the evaporator is called expansion. In addition,
the expansion valve controls the flow rate of the
refrigerant liquid while decreasing the pressure.
That is, the quantity of refrigerant liquid vaporized
inside the evaporator is determined by the quantity
of heat which must be removed at a prescribed
vaporization temperature. It is important that the
quantity of refrigerant be controlled to exactly the
right value.
COMPRESSOR
The compressor performs two main functions:
It compresses low-pressure and low-temperature
refrigerant vapor from the evaporator into high-
pressure and high-temperature refrigerant vapor to
the condenser. And it pumps refrigerant and
refrigerant oil through the A/C system.
6VD1/6VE1 engine on RHD model is equipped with
an invariable capacity five-vane rotary compressor
(DKV-14D Type).
The compressor sucks and compresses refrigerant
by the rotation of the vane installed to the shaft,
and always discharges a fixed amount of refrigerant
independent of the load of refrigerant.
The thermo sensor is installed to the front head of
the compressor to protect it by stopping its
operation when the refrigerant gas is insufficient or
when the temperature is abnormally high.
·OFF ....... 160 ±5¡C (320.0 ±41¡F)
·ON ........ 135 ±5¡C (275.0 ±41¡F)
Diesel Engine models and 6VD1/6VE1 engine on
LHD model are equipped with a swash plate type
compressor
Swash plate compressors have a swash (slanted)
plate mounted on the shaft. When the shaft turns,
the rotation of the swash plate is converted to
reciprocating piston motion which sucks in and
compresses the refrigerant gas.
Shaft seal (Lip type) is installed between the valve
plate and shaft & cylinder head to prevent
refrigerant gas leaks. A specified amount of
compressor oil is contained in the oil pan.
This oil is supplied to the cylinders, bearings, etc.,
by an oil pump which is connected to the swash
plate shaft.

AIR CONDITIONING 1B Ð 5
With some compressors the differential between
the intake pressure and discharge pressure
generated while the compressor is operating is
used for lubrication instead of an oil pump.
The specified amount of the DKV-14D, DKS-15CH
and HD6 compressors oil is 150cc (4.2 Imp fl oz).
Also, compressor oil to be used varies according to
the compressor model. Be sure to avoid mixing
two or more different types of oil.
If the wrong oil is used, lubrication will be poor and
the compressor will seize or malfunction.
The magnetic clutch connector is a waterproof type.
MAGNETIC CLUTCH
The compressor is driven by the drive belt from the
crank pulley of the engine. If the compressor is
activated each time the engine is started, this
causes too much load to the engine. The magnetic
clutch transmits the power from the engine to the
compressor and activates it when the air
conditioning is ÒONÓ. Also, it cuts off the power
from the engine to the compressor when the air
conditioning is ÒOFFÓ. (Magnetic clutch repair
procedure can be found in Section 1D.)
CONDENSER
The condenser assembly in front of the radiator,
which carry the refrigerant and cooling fins to
provide rapid transfer of heat.
Also, it functions to cool and liquefy the high-
pressure and high-temperature vapor sent from the
compressor by the radiator fan or outside air.
A condenser may malfunction in two ways: it may
leak, or it may be restricted. A condenser restriction
will result in excessive compressor discharge
pressure. If a partial restriction is present, the
refrigerant expands after passing through the
restriction.
Thus, ice or frost may from immediately after the
restriction. If air flow through the condenser or
radiator is blocked, high discharge pressures will
result. During normal condenser operation, the
refrigerant outlet line will be slightly cooler than the
inlet line.
The vehicle is equipped with the condenser of the
parallel flow type condenser. A larger thermal
transmission area on the inner surface of the tube
allows the radiant heat to increase and the
ventilation resistance to decrease.
The refrigerant line connection has a bolt at the
block joint, for easy servicing.
RECEIVER/DRIER
The receiver/drier performs four functions;
·As the quantity of refrigerant circulated varies
depending on the refrigeration cycle conditions,
sufficient refrigerant is stored for the refrigera-
tion cycle to operate smoothly in accordance
with fluctuations in the quantity circulated.
·The liquefied refrigerant from the condenser is
mixed with refrigerant gas containing air
bubbles. If refrigerant containing air bubbles is
sent to the expansion valve, the cooling
capacity will decrease considerably. Therefore,
the liquid and air bubbles are separated and
only the liquid is sent to the expansion valve.
·The receiver/drier utilizes a filter and dryer to
remove the dirt and water mixed in the cycling
refrigerant.
·The sight glass, installed atop the receiver/
drier, show the state of the refrigerant.
A receiver/drier may fail due to a restriction inside
the body of the unit. A restriction at the inlet to the
receiver/drier will cause high pressures.
Outlet restrictions will be indicated by low pressure
and little or no cooling. An excessively cold
receiver/ drier outlet may indicate a restriction.
The receiver/drier of this vehicle is made of
aluminum with a smaller tank. It has 300 cc
(8.5 Imp fl oz) refrigerant capacity.
The refrigerant line connection has a bolt at the
block joint, for easy servicing.
DKV-14D TYPE
DKS-15CH TYPE
HD6 TYPE
Magnetic clutch
CompressorSuction side
Discharge side
Compressor Magnetic clutch
852RW031 871RY00012
871RY00011