Expansion Tank Cap 17117639024 BMW Mini Peugeot Vauxhall Rolls-Royce.

Description

The Coolant Expansion Tank Pressure Cap (Part # 17117639024) is a 1.45 bar (145 kPa / ~21 PSI) pressure-regulating cap used across various BMW, MINI, PSA Group (Peugeot/Citroën), Vauxhall/Opel, and Rolls-Royce vehicles.

Unlike older 2.0 bar (200 kPa) BMW caps, this 1.45 bar cap is specifically engineered for systems operating at slightly lower baseline system pressures to reduce stress on plastic coolant tanks, thermostat housings, and hose connectors while preserving optimum anti-boil protection.

Technical Specifications & OEM Cross-References

Multi-Brand Vehicle Fitment

1. BMW

Fits various models equipped with 1.45 bar system specifications:

• 1 Series / 2 Series: F20, F21, F22, F23

• 3 Series / 4 Series: F30, F31, F34 GT, F32, F33, F36 Gran Coupe

• 5 Series / 6 Series / 7 Series: F10, F11, F07 GT, F12, F13, F01, F02, F03

• X Series: X1 (E84, F48), X3 (F25), X4 (F26), X5 (F15), X6 (F16)

2. MINI

Fits 2nd & 3rd Generation MINI models (N12, N14, N16, N18, B38, B48 engines):

• MINI Cooper / Cooper S / JCW: R55 Clubman, R56 Hatchback, R57 Convertible, R58 Coupe, R59 Roadster (2007–2015)

• MINI Countryman / Paceman: R60 Countryman, R61 Paceman (2010–2016)

• MINI F-Series: F55, F56, F54 Clubman, F60 Countryman (2014+)

3. Peugeot & Citroën (PSA Group)

Fits vehicles sharing EP6 / Prince 1.6L engines co-developed with BMW:

• Peugeot: 207, 208, 308, 508, 2008, 3008, 5008, RCZ (1.4 VTi, 1.6 VTi, 1.6 THP)

• Citroën: C3, C4, C5, DS3, DS4, DS5 (1.4 VTi, 1.6 VTi, 1.6 THP)

4. Vauxhall / Opel

• Models: Grandland X, Crossland X (PSA-platform models sharing Prince engine architecture and cooling components)

5. Rolls-Royce

• Models: Ghost (RR4), Wraith (RR5), Dawn (RR6) – 6.6L V12 N74 platforms

Function & Symptoms of Failure

Key Functions

• Maintains exact 1.45 bar cooling system pressure to raise the coolant boiling point above 115°C (239°F).

• Features a spring-loaded relief valve that safely vents excessive steam or pressure to prevent cracked expansion tanks.

• Vacuum check valve pulls air/fluid back in as the engine cools down to prevent collapsed coolant hoses.

Common Failure Symptoms

• Persistent “Low Coolant Level” warnings without visible hose leaks (caused by vapor escaping past worn internal cap seals).

• White crusty coolant residue around the neck of the expansion tank.

• Overheating under load due to loss of system pressure.

• Soft, collapsed upper radiator hose when the engine is completely cold.