Infiniti Q45. Manual - part 278

OVERHEATING CAUSE ANALYSIS

CO-5

C

D

E

F

G

H

I

J

K

L

M

A

CO

Except cool-
ing system 
parts mal-
function

—

Overload on engine

Abusive driving

High engine rpm under no 
load

Driving in low gear for 
extended time

Driving at extremely high 
speed

Powertrain system mal-
function

—

Installed improper size 
wheels and tires

Dragging brakes

Improper ignition timing

Blocked or restricted air 
flow

Blocked bumper

—

—

Blocked radiator grille

Installed car brassiere

Mud contamination or 
paper clogging

Blocked radiator

—

Blocked condenser

Blocked air flow

Installed large fog lamp

Symptom

Check items

CO-6

COOLING SYSTEM

COOLING SYSTEM

PFP:21020

Cooling Circuit

NBS001PL

SBIA0340E

COOLING SYSTEM

CO-7

C

D

E

F

G

H

I

J

K

L

M

A

CO

System Chart

NBS001PM

PBIC0160E

CO-8

ENGINE COOLANT

ENGINE COOLANT

PFP:KQ100

Inspection

NBS001PN

CHECKING ENGINE COOLANT LEVEL

●

Check if the reservoir tank engine coolant level is within “MIN” to
“MAX” when engine is cool.

●

Adjust engine coolant as necessary.

CHECKING COOLING SYSTEM FOR LEAKS

To check for leakage, apply pressure to the cooling system with
the radiator cap tester (commercial service tool) and the radiator cap
tester adapter (SST).

WARNING:

Do not remove radiator cap when engine is hot. Serious burns
could occur from high pressure engine coolant escaping from
thermostat housing.

CAUTION:

Higher pressure than specified may cause radiator damage.
NOTE:
In a case that engine coolant decreases, replenish radiator with engine coolant.

●

If anything is found, repair or replace damaged parts.

Changing Engine Coolant

NBS001PO

WARNING:

●

To avoid being scalded, do not change engine coolant when engine is hot.

●

Wrap a thick cloth around radiator cap and carefully remove radiator cap. First, turn radiator cap a
quarter of a turn to release built-up pressure. Then turn radiator cap all the way.

DRAINING ENGINE COOLANT

1.

Remove grommet from engine undercover.

2.

Open radiator drain plug at the bottom of radiator, and remove radiator cap. 

When draining all of engine coolant in the system, open water drain plugs on engine cylinder block.
Refer to 

EM-84, "DISASSEMBLY"

 .

3.

Check drained engine coolant for contaminants such as rust, corrosion or discoloration.
If contaminated, flush the engine cooling system. Refer to 

CO-10, "FLUSHING COOLING SYSTEM"

 .

4.

Remove reservoir tank as necessary, drain engine coolant and clean reservoir tank before installing.

SMA412B

Testing pressure

: 157 kPa (1.6 kg/cm

2

 , 23 psi)

PBIC0953E

PBIC2775E