Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 804

ENGINE COOLING (6VD1 3.2L)

6B–3

Thermostat

The thermostat is a wax pellet type with a air hole(1) and is
installed in the thermostat housing.

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Radiator

The radiator is a tube type with corrugated fins. In order to
raise the boiling point of the coolant, the radiator is fitted
with a cap in which the valve is operated at 88.2 

∼

 117.6

kPa (12.8 

∼

 17.0 psi) pressure. (No oil cooler provided for

M/T)

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Antifreeze Solution

D

Relation between the mixing ratio and freezing
temperature of the EC varies with the ratio of
anti–freeze solution in water. Proper mixing ratio can
be determined by referring to the chart. Supplemental
inhibitors or additives claiming to increase cooling
capability that have not been specifically approved by
Isuzu are not recommended for addition to the cooling
system.

D

Calculating mixing ratio

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NOTE: Antifreeze solution + Water = Total cooling
system capacity.

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Total Cooling System Capacity

D

M/T 8.8Lit (2.32Us gal)

D

A/T 8.4Lit (2.22Us gal)

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6B–4

ENGINE COOLING (6VD1 3.2L)

D

Mixing ratio

Check the specific gravity of engine coolant in the
cooling system temperature ranges from 0

°

C to 50

°

C

using a suction type hydrometer, then determine the
density of the engine coolant by referring to the table.

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Diagnosis

Engine Cooling Trouble

Condition

Possible cause

Correction

Engine overheating

Low Engine Coolant level

Replenish

Thermo meter unit faulty

Replace

Faulty thermostat

Replace

Faulty Engine Coolant temperature
sensor

Repair or replace

Clogged radiator

Clean or replace

Faulty radiator cap

Replace

Low engine oil level or use of
improper engine oil

Replenish or change oil

Clogged exhaust system

Clean exhaust system or replace
faulty parts

Faulty Throttle Position sensor

Replace throttle valve assembly

Open or shorted Throttle Position
sensor circuit

Repair or replace

Damaged cylinder head gasket

Replace

Engine overcooling

Faulty thermostat

Replace

Engine slow to warm–up

Faulty thermostat

Replace

Thermo unit faulty

Replace

ENGINE COOLING (6VD1 3.2L)

6B–5

Draining and Refilling Cooling
System

Before draining the cooling system, inspect the system
and perform any necessary service to ensure that it is
clean, does not leak and is in proper working order. The
engine coolant (EC) level should be between the “MIN”
and “MAX” lines of reserve tank when the engine is cold.
If low, check for leakage and add EC up to the “MAX” line.
There should not be any excessive deposit of rust or
scales around the radiator cap or radiator filler hole, and
the EC should also be free from oil.
Replace the EC if excessively dirty.

1. Completely drain the cooling system by opening the

drain plug (2) at the bottom of the radiator.

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2. Remove the radiator cap.

WARNING: TO AVOID THE DANGER OF BEING
BURNED, DO NOT REMOVE THE CAP WHILE THE
ENGINE AND RADIATOR ARE STILL HOT.
SCALDING FLUID AND STEAM CAN BE BLOWN OUT
UNDER PRESSURE.

3. Disconnect all hoses from the EC reserve tank.

Scrub and clean the inside of the reserve tank with
soap and water. Flush it well with clean water, then
drain it.  Install the reserve tank and hoses.

4. Refill the cooling system with the EC using a solution

that is at least 50 percent antifreeze but no more than
70 percent antifreeze.

Procedure for filling with coolant (in case of full change)

D

Make sure that the engine is cool.

D

Open radiator cap pour coolant up to filler neck.

D

Pour coolant into reservoir tank up to “MAX” line.

D

Tighten radiator cap and start the engine. After idling
for 2 to 3 minutes, stop the engine and reopen radiator
cap. If the water level is lower, replenish.

WARNING: WHEN THE COOLANT IS HEATED TO A
HIGH TEMPERATURE, BE SURE NOT TO LOOSEN
OR REMOVE THE RADIATOR CAP. OTHERWISE YOU
MIGHT GET SCALDED BY NOT VAPOR OR BOILING
WATER. TO OPEN THE RADIATOR CAP, PUT A
PIECE OF THICK CLOTH ON THE CAP AND LOOSEN
THE CAP SLOWLY TO REDUCE THE PRESSURE
WHEN THE COOLANT HAS BECOME COOLER.

D

After tightening radiator cap, warm up the engine at
about 2000 rpm. Set heater adjustment to the highest
temperature position, and let the coolant circulate
also into heater water system.

D

Check to see the thermostat has opened through the
needle position of water thermometer, conduct a
5–minute idling again and stop the engine.

D

When the engine has been cooled, check filler neck
for water level and replenish if required. Should
extreme shortage of coolant is found, check the
cooling system and reservoir tank hose for leakage.

D

Pour coolant into the reservoir tank up to “MAX” line.

6B–6

ENGINE COOLING (6VD1 3.2L)

Water Pump

Water Pump and Associated Parts

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Legend

(1) Timing Belt
(2) Idle Pulley

(3) Water Pump Assembly
(4) Gasket

Removal

1. Disconnect battery ground cable.
2. Drain coolant.
3. Radiator hose (on inlet pipe side).
4. Remove timing belt. Refer to “Timing Belt” in this

manual.

5. Remove Idle pulley.
6. Remove water pump assembly.
7. Remove gasket.

Inspection

Make necessary repair and parts replacement if extreme
wear or damage is found during inspection. Should any of
the following problems occur, the entire water pump
assembly must be replaced:

D

Crack in the water pump body

D

EC leakage from the seal unit

D

Play or abnormal noise in the bearing

D

Cracks or corrosion in the impeller.

Installation

1. Install gasket, clean the mating surface of gasket

before installation.

2. Install water pump assembly and tighten bolts to the

specified torque.

Torque: 25 N·m (2.5 kg·m/18 lb ft)

D

Tightening order
The tightening order are in the illustrate.

NOTE: To prevent the oil leakage, apply the LOCTITE
262 or an equivalent, to the arrow marked fixing bolt
thread.

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