JLRTB02127NAS6

TECHNICAL BULLETIN
05 NOV 2025

© Jaguar Land Rover North America, LLC
NOTE: The information in Technical Bulletins is intended for use by trained, professional
Technicians with the knowledge, tools, and equipment required to do the job properly
and safely. It informs these Technicians of conditions that may occur on some vehicles,
or provides information that could assist in proper vehicle service. The procedures
should not be performed by 'do-it-yourselfers'. If you are not a Retailer, do not assume
that a condition described affects your vehicle. Contact an authorized Land Rover
service facility to determine whether this bulletin applies to a specific vehicle.
INFORMATION

This bulletin supersedes TSB JLRTB02127NAS5/2025 dated 28 MAR 2025, which
should either be destroyed or clearly marked to show it is no longer valid (e.g. with a line
across the page). Only refer to the electronic version of this Technical Bulletin in TOPIx.
Changes are highlighted in blue

SECTION:

303-03A

SUBJECT
/CONCERN:

Engine Coolant Level Low with no Visible Loss of Coolant

AFFECTED VEHICLE RANGE:

MODEL:
Range Rover (LK)

MODEL YEAR:
2022-2024

VIN:
000001-234058

ASSEMBLY PLANT:
Solihull

MODEL:
Range Rover Sport (L1)

MODEL YEAR:
2023-2024

VIN:
000001-400762

ASSEMBLY PLANT:
Solihull

MARKETS:

NORTH AMERICA

CONDITION
SUMMARY:

SITUATION:
A customer may express a concern that there is a 'Coolant Level Low' message
displayed on the instrument panel cluster and the coolant level low or close to minimum,
or that the coolant level requires frequently topping up.
This bulletin has been updated to align the Service Repair Operation (SRO)s with
the JLRTB02127 Workflow.
CAUSE:
Permeation of water content from the engine coolant through plastic pipes.
ACTION:
Follow the Service Instruction below.

The following applies to:



All Vehicles

PARTS:

NOTES:
*When stock of 104123458 is depleted order 104123633.
**An allowance equivalent to £5.00 Sterling has been allocated to locally
source engine coolant.

PART NUMBER

DESCRIPTION

QUANTITY

*104123458 or 104123633

Coolant Expansion Tank

1

**ZZZ001

Engine Coolant

£5

The following applies to:



INGENIUM I6 3.0L Petrol / INGENIUM I6 3.0L Petrol PHEV Vehicles Only

PARTS:

NOTES:
*When stock of 202123501 is depleted order 202123527.
**The 4 undershield fixing retainers (LR165498) are required for the Plug-in
Hybrid Electric Vehicle (PHEV) vehicles only.

PART NUMBER

DESCRIPTION

QUANTITY

*202123501 or 202123527

Fuel Supply Line

1

202123508

Fuel Supply Line to Expansion Tank Clip

1

LR185830

Fuel Supply Line to Vapour Damper Bracket Clip

1

**LR165498

Undershield Fixing Retainer

4

TOOLS:



JLR-1839
Cooling system pressure
tester



JLR-303-1720-02
Coolant System
Pressure Tester Cap and
Adapter

WARRANTY:

NOTES:
Repair procedures are under constant review, and therefore times are subject
to change; those quoted here must be taken as guidance only. Use TOPIx to
obtain the latest repair time.
The JLR claims submission system requires the use of causal part numbers.
Labor only claims must show the causal part number with a quantity of zero.

SRO

TIME
(HOURS)

CONDITION
CODE

CAUSAL
PART

JLRTB - Coolant Level Low - INGENIUM I6
3L Diesel / V8 T/C 4.4L Petrol

99.04.11

0.8

*

LR151660

JLRTB - Coolant Level Low + Fuel Supply
Line - INGENIUM I6 3L Petrol

99.04.11.01

3.8

*

LR178362

JLRTB - Coolant Level Low + Fuel Supply
Line - INGENIUM I6 3L Petrol - PHEV

99.04.11.01

4.0

*

LR178362

DESCRIPTION

NOTE:
Normal Warranty procedures apply.

COOLING SYSTEM PRESSURE TEST

WARNING:
Injury such as scalding could be caused by escaping steam or coolant. The vehicle
cooling system must be cool prior to completing this procedure.

CAUTIONS:
Engine coolant can damage the paint finished surfaces. If spilt, immediately
remove the fluid and clean the area with water.
Never remove the coolant expansion tank filler cap under any circumstances
while the engine is operating. Failure to follow this instruction may result in
damage to the engine.
Mating faces must be are clean and free of foreign material.

NOTES:
This procedure contains some variation in the illustrations depending on the
vehicle specification, but the essential information is always correct.

This procedure contains illustrations showing certain components removed to
provide extra clarity.

1.



Inspect the coolant expansion tank.
If coolant expansion tank 'B' is installed do not continue with this bulletin.
Repair as necessary with reference to TOPIx.
If coolant expansion tank 'A' is installed continue to the next step.

2.

Inspect the coolant level in the coolant expansion tank. If the coolant is at the
maximum level in the coolant expansion tank and the 'Coolant Level Low'
message is displayed on the instrument panel cluster do not continue with this
bulletin. Repair as necessary with reference to TOPIx.

3.

NOTE:
Any related repairs must be claimed as a separate warranty claim.

Visually check the cooling system for signs of engine coolant leaks and distorted
hoses. Make sure all the cooling system components are correctly installed.
If there are any visual signs of engine coolant leaks do not continue with
this bulletin. Repair as necessary with reference to TOPIx.
If there are no visual signs of engine coolant leaks continue to the next
step.

NOTE:
The following procedure will enable the cooling system to be pressure tested for
condition and leaks. Step 4 will check the expansion tank filler cap seal and the
filler cap for leaks. Step 6 will check the entire cooling system.

4.

WARNING:
Release the cooling system pressure by slowly turning the coolant
expansion tank cap a quarter of a turn. Cover the expansion tank cap
with a thick cloth to prevent the possibility of scalding. Failure to follow
this instruction may result in personal injury.

CAUTION:
Be prepared to collect escaping coolant.



Remove the coolant expansion tank filler cap.

5.

WARNING:
Do not pressurize the coolant expansion tank filler cap to the maximum
pressure shown on the filer cap.

NOTE:
Any related repairs must be claimed as a separate warranty claim.



Using the correct adapter connect the cooling system pressure tester to the
coolant expansion tank filler cap.
Slowly pressurize the coolant expansion tank filler cap 1.6 bar (23 psi) as
shown on the gauge. No significant drop in pressure must be noted on the
coolant expansion tank filler cap. If after 5 minutes the pressure
significantly drops, the coolant expansion tank filler cap must be replaced.
If 1.6 bar (23 psi) is reached with no drop in pressure, validate the coolant
expansion tank filler cap by increasing the pressure to between 1.7 bar (25
psi) to 2.1 bar (30 psi) to confirm the valve is operating as intended. The
pressure must be released through the coolant expansion tank filler cap.
If the coolant expansion tank filler cap fails this test, the coolant expansion
tank cap must be replaced. This must be completed under related repairs
and must be claimed as a separate warranty claim.

6.

Depressurize and remove the coolant expansion filler tank cap from the cooling
system pressure tester.
Disassemble the cooling system pressure tester.

7.

CAUTION:
Do not exceed 2.0 bar (28 psi) when pressurizing the cooling system.

NOTE:
If the pressure continues to drop after the initial tolerance, the cooling
system must to be checked for leaks.



Using the correct adapter connect the cooling system pressure tester to the
coolant expansion tank.
Slowly pressurize the cooling system until 2.0 bar (28 psi) is shown on the
gauge.
No significant drop in pressure must be noted on the cooling pressure
tester gauge. If after 5 minutes the pressure significantly drops, inspect the
cooling system for leaks. A pressure drop of 0.15 bar (1psi) in the first
minute is considered normal operation.

8.



Depressurize and remove the cooling system pressure tester.

9.

10.

Install the coolant expansion tank filler cap.

NOTE:
Any related repairs must be claimed as a separate warranty claim.

Visually check the cooling system for signs of engine coolant leaks.
If there are any visual signs of engine coolant leaks do not continue with
this bulletin. Repair as necessary with reference to TOPIx.
If there are no visual signs of engine coolant leaks complete the SERVICE
INSTRUCTION section of this bulletin.

SERVICE INSTRUCTION:

INGENIUM I6 3.0L Petrol, INGENIUM I6 3.0L Petrol PHEV Vehicles Only:
1.

Remove the fuel supply line (see TOPIx Workshop Manual section 310-01: Fuel
Tank and Lines - Removal and Installation - Fuel Supply Line).

All Vehicles:

2.

Renew the coolant expansion tank (see TOPIx Workshop Manual section 30303: Engine Cooling - Removal and Installation - Coolant Expansion Tank).

INGENIUM I6 3.0L Petrol, INGENIUM I6 3.0L Petrol PHEV Vehicles Only:
3.

Install the new fuel supply line (see TOPIx Workshop Manual section 310-01:
Fuel Tank and Lines - Removal and Installation - Fuel Supply Line).

All Vehicles:
4.

Check the coolant concentration (see TOPIx Workshop Manual section 303-03:
Engine Cooling - General Procedure - Cooling System Concentration Check).