Jaguar XJ (X350). Manual — part 611

3

—

Water pump

Water Pump

The water pump is of a conventional design and is driven by the crankshaft pulley through the

accessory drive belt. The water pump belt tension is maintained by an automatic drive belt tensioner.

For additional information, refer to Accessory Drive Belt Tensioner - 2.7L Diesel (303-05)

Thermostat

The thermostat is located in the thermostat housing and allows rapid engine warm-up by restricting

coolant flow through the radiator below approximately 92°C (198°F). The thermostat also assists in

keeping the engine operating temperature within predetermined limits.

When the engine is cold and the thermostat is closed, coolant flows from the water pump through

the engine. It then returns to the water pump through the upper coolant hose.

When the engine is warm and the thermostat is open, coolant flows into the radiator through the

upper coolant hose. It then returns to the water pump from the radiator through the lower coolant

hose.

The heater core is on a parallel circuit and is unaffected by the position of the thermostat.

Radiator

The radiator is of aluminium construction with plastic end tanks. Foam seals are fitted to the radiator

to prevent the cooling air from by passing the radiator core. A coolant drain plug is provided in the

lower coolant end tank of the radiator for the draining of the coolant. The cooling fan shroud is

attached to the radiator.

Cooling Fan

A single, variable speed cooling fan motor is attached to a fan shroud located behind the radiator.

The speed is determined by the Engine Coolant Temperature (ECT) and the air conditioning pressure

and transmission oil temperature.

Under hot operating conditions, the fan may continue to operate for four minutes after the engine

has been switched off.

Coolant Recovery System

A pressurized coolant expansion tank system is used which continuously separates the air from the

cooling system and replenishes the system through the coolant expansion tank outlet hose, attached

to the heater return hose.

A continuous vent from the engine and radiator to the coolant expansion tank prevents air locks

from forming in the cooling system.

A manual bleed point is provided on the coolant reservoir.

The coolant expansion tank serves as the location for:

•

Service fill.

•

Coolant expansion during warm-up.

•

Air separation during operation.

•

System pressurization by the coolant pressure cap.

•

The coolant expansion tank is designed to have approximately 0.5 to 1 liter of air when cold
to allow for coolant expansion.

Engine Coolant

The long life engine coolant is formulated to last for five years or 240,000 km (150,000 miles). The

coolant is silicate free and orange in color. The long life engine coolant must not be mixed with

conventional engine coolant.

Coolant Flow Diagram (Thermostat open)

www.

Item

Part Number

Description

1

—

Radiator

2

—

Auxiliary coolant flow pump

3

—

Coolant expansion tank

4

—

Auxiliary heater

5

—

Engine oil and fuel cooler

6

—

Heater matrix

7

—

Right-hand exhaust gas recirculation cooler

8

—

Left-hand exhaust gas recirculation cooler

9

—

Engine coolant outlet

10

—

Engine coolant inlet

11

—

Water pump

12

—

Transmission oil cooler

13

—

Thermostat

14

—

Transmission oil cooler coolant control valve

Diagnosis and testing

Engine Cooling

Inspection and Verification

1 . Verify the customer concern.

2 . Visually inspect for obvious signs of mechanical or electrical damage.

Mechanical

Electrical

•

Coolant leaks

•

Hoses

•

Expansion tank

•

Radiator

•

Accessory drive belt

•

Cooling fan

•

Battery charge and condition

•

Fuses

•

Harnesses and connectors

•

Engine coolant temperature (ECT) sensor (if equipped)

3 . If an obvious cause for an observed or reported concern is found, correct the cause (if possible)

before proceeding to the next step.

4 . If the cause is not visually evident, use the Jaguar approved diagnostic system or a scan tool to

retrieve the fault codes. For a full list of powertrain DTCs,

Electronic Engine Controls

Pinpoint tests

PINPOINT TEST G557183p1 : LOSS OF
COOLANT

G557183t1 : VISUAL INSPECTION

1. Visually inspect for loss of coolant 2. Following the instructions for your workshop's pressure

tester, carry out a system pressure test.

•

Is the engine cooling system leaking?

-> Yes

Rectify the source of the leak as indicated by the test.

Cooling System Draining, Filling and Bleeding TEST the system for normal operation.

www.