Isuzu KB P190. Manual — part 788

Engine Cooling – V6 Engine

Page 6B1–17

3

Top up as required, using a 50 / 50 mix of clean water and the recommended coolant, which is either DEX-COOL®
long-life coolant or its equivalent, known as Extended Life Anti-freeze Coolant conforming to GM specification
6277M. Refer to 3.2 Coolant Maintenance and 3.3 Draining and Filling Cooling System in this Section, for the
necessary procedures and further information.

3.2 Coolant

Maintenance

Do not mix different types of anti-freeze or
corrosion inhibitors, as they may be
incompatible. If a different type has been used
in the cooling system, flush the system with
clean water, refer to 3.4 Cleaning

Cooling

System – Cooling System Flush in this
Section and refill cooling system with the
correct coolant. Refer to 3.3 Draining

and

Filling Cooling System in this Section.

The cooling system is designed to use a coolant (a mixture of ethylene glycol antifreeze with added corrosion inhibitors,
and water), rather than plain water. The use of glycol also raises the boiling point and increases the cooling system
efficiency. For this reason, it is of the utmost importance that the correct concentration level of ethylene glycol in the
cooling system is maintained.

Addition of plain water into the cooling system when 'topping-up' may dilute the coolant mixture to a point where the
antifreeze / anti-boil and corrosion inhibitor properties of ethylene glycol become ineffective.

The coolant should comprise of a mixture 50% ethylene glycol antifreeze / inhibitor with 50% clear, clean water.

Ethylene glycol conforming to the correct specification is either named DEX-COOL® long-life coolant or its equivalent,
known as Extended Life Anti-freeze Coolant conforming to GM specification 6277M. Both are available in a number of
different quantities. Check the current release of Partfinder™ for specific details.

Engine Cooling – V6 Engine

Page 6B1–18

Topping Up the Cooling System

Under normal operating conditions, the cooling system
should not be topped up at the coolant filler cap. The level
can be checked at the coolant recovery reservoir, and
coolant (in the correct concentration with clear, clean
water) added as necessary to bring the level between the
MAX and MIN indicator lines on the coolant recovery
reservoir, as shown in Figure 6B1 – 14, when the engine is
cold.

Figure 6B1 – 14

Testing Coolant Concentration

To ensure the specified ethylene glycol concentration is maintained in the engine coolant, the coolant concentration must
be checked at the time or distance intervals outlined in the Owner’s Handbook or Service Booklet in the glove box.

N O T E

• While a number of coolant concentration

measuring devices are available, the two
preferred types are as described.

• The procedures detailed, apply to either

coolant type used.

Method 1 – Refractometer

N O T E

• Coolant tester, Tool No. J26568,

automatically compensates for temperature.

• Ensure that the eyepiece of the tester is free

of coolant before looking through it.

• Before each use, swing back the plastic cover

at the slanted end of the coolant tester,
exposing the measuring window and the
bottom of the plastic cover. Carefully wipe the
measuring window dry with a tissue or clean,
soft cloth. Close the plastic cover.

1

Check the calibration of the coolant tester as follows:

Engine Cooling – V6 Engine

Page 6B1–19

a

Place a few drops of distilled water (between 21 and 29° C) onto the measuring window, then close the
plastic cover.

b

Point the tester toward any light source, look into the eyepiece and check that the indicated reading is zero. If
not, then re-calibrate the tester as detailed at the end of this Test Method, Calibrating the Tester.

2

Release the tip of the bulb pump from under the
refractometer body. It is not necessary to remove the
complete pump from the tool.

Refer

to

3.1 Service Notes in this

Section, for important safety items.

3

Carefully remove the coolant filler cap.

4

Insert the tube of the pump into the coolant, and
then press the bulb to obtain a sample.

5

Bend the tube around and insert the end into the
cover plate opening.

Figure 6B1 – 15

6

Press the pump bulb to deposit a few drops of coolant onto the measuring surface. Do not open the plastic cover
when taking readings, as moisture evaporation will change the reading obtained.

7

Point the coolant tester toward any light source,
looking into the eyepiece.

a

The coolant protection reading is at the point
where the dividing line between the light and
dark, crosses the scale.

b

The scale for ethylene glycol (bold arrow) is
the reference scale for either DEX-COOL®
long-life coolant or its equivalent, known as
Extended Life Anti-freeze Coolant conforming
to GM specification 6277M.

N O T E

The temperature scale is reversed from that of
a conventional thermometer. Below zero
readings are on the upper half of the scale.

8

A reading between – 30 and – 52

°C (corresponding

to a coolant concentration between 45 to 60%), is
satisfactory for the HFV6 engine cooling system.

Figure 6B1 – 16

Engine Cooling – V6 Engine

Page 6B1–20

COOLANT CONCENTRATION

Litres Of Coolant To Be Added

Concentration

Reading %

Automatic Transmission

Manual Transmission

0

4.95 5.15

5

4.46 4.62

10

3.96 4.12

15

3.47 3.61

20

2.97 3.08

25

2.48 2.57

30

1.98 2.01

35

1.48 1.54

40

0.99 1.05

45

0.50 0.52

50

0 0

N O T E

If the reading is not clear, then properly clean
and dry the measuring surface, then conduct
another test. Also ensure that there is
sufficient fluid on the measuring prism.

9

If the reading shows that the concentration level of
the coolant is inadequate, refer to the Coolant
Concentration table to determine the amount of
coolant that needs to be added to the coolant
recovery reservoir.

10

Start and run the engine until normal operating
temperature is reached, to allow the added coolant
to be distributed throughout the engine cooling
system.

Figure 6B1 – 17