Australian 4WD Action – August 2019

WHY YOU SHOULDN’T

MIX COOLANTS

MECHANICAL VS ELECTRIC

FANS - WHAT’S BEST?

Mixing two different types of coolant is not good for your engine.

Incompatible glycols mixed together, even if the same colour, turn

acidic, and can quickly eat through soft metals. So essentially,

mixing coolants could be eating your engine away from the inside

out. Your best bet is to flush the entire cooling system once a year

or at the same time as you carry out any repairs.

Fans driven by the engine in the majority of cases are higher

flowing than electric fans, as the mechanical drive will not fall

off at the higher airflow rates like the electric fan.

“If you look at almost all diesel engines, these high-torque,

low-speed engines are designed with mechanical fans. Having

a shroud on these setups is important as well, otherwise the

fan will pull air from the path of least resistance, and in almost

all cases this is not from the radiator.

Check for air

lock and purge

cooling system.

Recheck. Are

both heater

hoses hot and

does the heater

work? Water pump fault

• Replace

Temperature

gauge, sensor or

wiring fault -

Repair or replace

Engine may be

running too rich

• Replace air filter

Engine may be

running too rich

• Check and dyno
  tune

RADIATOR

MAY BE

UNDERSIZED

• Upgrade
  Radiator

Check air flow

through engine

bay -

Remove bash

plates and ensure

all plastic cowlings

are fitted

Cooling system okay! -

Blocked heater Lock it in low and go-go-go!
core -
Remove and
service

NO

yes

yes

yes

yes

yes

yes

yes

NO

NO

yes NO NO NO NO NO

Check

temperature

gauge, sensor

and wiring

operation.

Were any

faults found?

Is the engine

blowing

excessive

black smoke?

Or fitted with

a perfor-

mance chip?

Has engine

power being

increased by

more than

25% over

factory?

Is the engine still overheating?

Check air

filter. Is it

blocked?

Inspect water

pump for

coolant leaks

and listen for

noise from

the bearing.

Are there any

bearing leaks

or noises?

At full

operation

temp, set

cabin heater

to full heat

then

carefully feel

both heater

hoses. Are

they both hot

and does the

heater work?

RED VS GREEN COOLANT

So what about red verses green coolant? Generally speaking,

green coolant is made using traditional ‘ethylene’ glycol. Red

coolant uses ‘propylene’ glycol, which essentially has much

the same anti-freeze, anti-boil and anti-corrosion properties

as green coolant, but it’s a newer more environmentally-

friendly version.

10

THINGS

EVERYONE

GETS

WRONG

CAUSE EFFECT

1 Incorrect coolant mix This can reduce the

coolant’s effect and eat

away at your engine

2 Not running a fan shroud Changes air flow character-

istics through the radiator

at slow speeds

3

Fitting the wrong tempera-

ture thermostat

Thermostat doesn’t open at

the right time

4

Missing inner wheel-well

plastic guards

Decreases air flow through

the radiator

5 Not cleaning the radiator

core often enough

Blocks air flow through the

radiator

6 Not changing the air filter

regularly

Causes the engine to run

richer and hotter

7 Winding up the fuel screw on

older diesels or installing a

diesel chip with an aggres-

sive tune that’s too rich

Rich engines run hotter

8 Not servicing brakes

regularly

Dragging brakes work the

engine harder

9

Fitting full-length bash

plates that block air from

exiting the engine bay

Decreases air flow through

the radiator

10 Not upgrading the radiator

soon enough

Larger tyres, more power

and towing heavy loads all

cause the engine to work

harder and run hotter

T E C H T A L K

ES

SE

N

TI

AL

(^) C
O
O
LI
N
G
(^) S
Y
ST
EM
(^) M
O
D
S