Water pump

The primary function of the water pump is to circulate coolant throughout the engine's cooling system. This helps maintain the engine at an optimal operating temperature by transferring heat away from the engine components to the radiator, where the coolant is cooled before being recirculated.

OE Number

038121011C	038121011G	038121011CX	ME6M218501B1A
38121011DX	038121011KX	038121011J	1673518
03L121011BX	038121011JX	038121011K	1457395
038121011D	038121011HX	68000693AB	1225896
03L121011G	038121011H	XM218501AA	1100635
03L121011B	038121011GX	RMXM218501AA	MN980134
03G121011	038121011DX	RM6M218501BA

Compatible Applications

AUDI A3 Convertible (8P7) (Year of Construction 04.2008 - 05.2013, 136 - 140 PS, Diesel)

AUDI A3 Hatchback (8L1) (Year of Construction 08.2000 - 05.2003, 100 - 130 PS, Diesel)

AUDI A3 Hatchback (8P1) (Year of Construction 05.2003 - 08.2012, 136 - 170 PS, Diesel)

AUDI A3 Sportback (8PA) (Year of Construction 09.2004 - 03.2013, 140 - 170 PS, Diesel)

AUDI A4 B5 Avant (8D5) (Year of Construction 03.2000 - 09.2001, 115 PS, Diesel)

AUDI A4 B5 Saloon (8D2) (Year of Construction 03.2000 - 11.2000, 116 PS, Diesel)

AUDI A4 B6 Avant (8E5) (Year of Construction 09.2001 - 12.2004, 101 - 130 PS, Diesel)

AUDI A4 B6 Saloon (8E2) (Year of Construction 11.2000 - 12.2004, 101 - 130 PS, Diesel)

AUDI A4 B6/B7 Convertible (8H7, 8HE) (Year of Construction 01.2006 - 03.2009, 136 - 140 PS, Diesel)

AUDI A4 B7 Avant (8ED) (Year of Construction 11.2004 - 06.2008, 116 - 170 PS, Diesel)

AUDI A4 B7 Saloon (8EC) (Year of Construction 11.2004 - 06.2008, 116 - 170 PS, Diesel)

AUDI A4 B8 Allroad (8KH) (Year of Construction 04.2009 - 05.2016, 136 - 170 PS, Diesel)

AUDI A4 B8 Avant (8K5) (Year of Construction 04.2008 - 12.2015, 120 - 170 PS, Diesel)

AUDI A4 B8 Saloon (8K2) (Year of Construction 11.2007 - 12.2015, 120 - 170 PS, Diesel)

AUDI A5 B8 Convertible (8F7) (Year of Construction 05.2009 - 06.2014, 163 - 170 PS, Diesel)

AUDI A5 B8 Coupe (8T3) (Year of Construction 08.2008 - 01.2017, 163 - 170 PS, Diesel)

AUDI A5 B8 Sportback (8TA) (Year of Construction 09.2009 - 01.2017, 136 - 170 PS, Diesel)

AUDI A6 C5 Avant (4B5) (Year of Construction 07.2000 - 01.2005, 115 - 130 PS, Diesel)

AUDI A6 C5 Saloon (4B2) (Year of Construction 07.2000 - 01.2005, 115 - 130 PS, Diesel)

AUDI A6 C6 Avant (4F5) (Year of Construction 06.2005 - 08.2011, 121 - 170 PS, Diesel)

AUDI A6 C6 Saloon (4F2) (Year of Construction 07.2004 - 03.2011, 121 - 170 PS, Diesel)

AUDI Q5 (8RB) (Year of Construction 11.2008 - 05.2017, 136 - 170 PS, Diesel)

AUDI TT Coupe (8J3) (Year of Construction 06.2008 - 06.2014, 170 PS, Diesel)

AUDI TT Roadster (8J9) (Year of Construction 06.2008 - 06.2014, 170 PS, Diesel)

FORD Galaxy Mk1 (WGR) MPV (Year of Construction 03.1995 - 05.2006, 90 - 115 PS, Diesel)

MITSUBISHI Grandis (NA4W) (Year of Construction 09.2005 - 03.2010, 136 - 140 PS, Diesel)

MITSUBISHI Lancer VIII Hatchback (CX_A) (Year of Construction 06.2008 - ..., 140 PS, Diesel)

MITSUBISHI Lancer VIII Saloon (CY_A, CZ_A) (Year of Construction 01.2008 - ..., 140 PS, Diesel)

MITSUBISHI Outlander II Off-Road (CW_W) (Year of Construction 02.2007 - 11.2012, 140 PS, Diesel)

SEAT Alhambra I (7V8, 7V9) (Year of Construction 04.1996 - 03.2010, 90 - 140 PS, Diesel)

SEAT Altea (5P1) (Year of Construction 03.2004 - ..., 136 - 170 PS, Diesel)

SEAT Altea XL (5P5, 5P8) (Year of Construction 10.2006 - ..., 136 - 170 PS, Diesel)

SEAT Exeo Saloon (3R2) (Year of Construction 12.2008 - 05.2013, 120 - 170 PS, Diesel)

SEAT Exeo ST (3R5) (Year of Construction 05.2009 - 05.2013, 120 - 170 PS, Diesel)

SEAT Ibiza III Hatchback (6L) (Year of Construction 03.2004 - 02.2008, 160 PS, Diesel)

SEAT Leon I Hatchback (1M1) (Year of Construction 09.2000 - 06.2006, 100 - 150 PS, Diesel)

SEAT Leon II Hatchback (1P1) (Year of Construction 07.2005 - 12.2012, 136 - 170 PS, Diesel)

SEAT Toledo II Saloon (1M2) (Year of Construction 10.2000 - 07.2004, 150 PS, Diesel)

SEAT Toledo III (5P2) (Year of Construction 04.2004 - 05.2009, 136 - 170 PS, Diesel)

SKODA Octavia I Combi (1U5) (Year of Construction 08.2000 - 12.2010, 100 - 130 PS, Diesel)

SKODA Octavia I Hatchback (1U2) (Year of Construction 09.2002 - 12.2010, 100 - 130 PS, Diesel)

SKODA Octavia II Combi (1Z5) (Year of Construction 02.2004 - 05.2013, 136 - 170 PS, Diesel)

SKODA Octavia II Hatchback (1Z3) (Year of Construction 02.2004 - 04.2013, 136 - 170 PS, Diesel)

SKODA Superb I Saloon (3U4) (Year of Construction 12.2001 - 03.2008, 101 - 140 PS, Diesel)

SKODA Superb II Estate (3T5) (Year of Construction 10.2009 - 05.2015, 140 - 170 PS, Diesel)

SKODA Superb II Hatchback (3T4) (Year of Construction 03.2008 - 05.2015, 140 - 170 PS, Diesel)

SKODA Yeti (5L) (Year of Construction 05.2009 - 12.2017, 140 - 170 PS, Diesel)

VW Beetle Convertible (5C7, 5C8) (Year of Construction 04.2012 - 07.2016, 140 PS, Diesel)

VW Beetle Hatchback (5C1, 5C2) (Year of Construction 04.2011 - 07.2016, 140 PS, Diesel)

VW Bora Saloon (1J2) (Year of Construction 12.1998 - 05.2005, 101 - 150 PS, Diesel)

VW Bora Variant (1J6) (Year of Construction 05.1999 - 05.2005, 101 - 150 PS, Diesel)

VW Caddy III Estate (2KB, 2KJ, 2CB, 2CJ) (Year of Construction 09.2007 - 08.2010, 140 PS, Diesel)

VW Caddy III Van (2KA, 2KH, 2CA, 2CH) (Year of Construction 09.2007 - 08.2010, 140 PS, Diesel)

VW Eos (1F7, 1F8) (Year of Construction 06.2006 - 08.2015, 140 PS, Diesel)

VW Golf IV Hatchback (1J1) (Year of Construction 12.1998 - 06.2005, 101 - 150 PS, Diesel)

VW Golf IV Variant (1J5) (Year of Construction 08.1999 - 06.2006, 101 - 150 PS, Diesel)

VW Golf Plus / Crossgolf (5M1, 521) (Year of Construction 01.2005 - 12.2013, 131 - 140 PS, Diesel)

VW Golf V Hatchback (1K1) (Year of Construction 10.2003 - 11.2008, 136 - 170 PS, Diesel)

VW Golf V Variant (1K5) (Year of Construction 06.2007 - 07.2009, 136 - 140 PS, Diesel)

VW Golf VI Hatchback (5K1) (Year of Construction 10.2008 - 05.2013, 110 - 170 PS, Diesel)

VW Golf VI Variant (AJ5) (Year of Construction 07.2009 - 07.2013, 140 PS, Diesel)

VW Jetta Mk5 (1K) (Year of Construction 08.2005 - 10.2010, 136 - 170 PS, Diesel)

VW Jetta Mk6 (162, 163, AV3, AV2) (Year of Construction 02.2011 - ..., 140 PS, Diesel)

VW New Beetle Convertible (1Y7) (Year of Construction 06.2003 - 09.2010, 100 - 105 PS, Diesel)

VW New Beetle Hatchback (9C1, 1C1) (Year of Construction 02.2001 - 09.2010, 101 - 105 PS, Diesel)

VW Passat B5 Estate (3B5) (Year of Construction 08.1998 - 11.2000, 101 - 115 PS, Diesel)

VW Passat B5 GP Estate (3BG, 3B6) (Year of Construction 11.2000 - 05.2005, 101 - 136 PS, Diesel)

VW Passat B5 GP Saloon (3BG, 3B3) (Year of Construction 11.2000 - 05.2005, 101 - 136 PS, Diesel)

VW Passat B5 Saloon (3B2) (Year of Construction 08.1998 - 11.2000, 101 - 115 PS, Diesel)

VW Passat B6 Saloon (3C2) (Year of Construction 03.2005 - 11.2010, 110 - 170 PS, Diesel)

VW Passat B6 Variant (3C5) (Year of Construction 08.2005 - 11.2010, 110 - 170 PS, Diesel)

VW Passat CC (357) (Year of Construction 05.2008 - 01.2012, 136 - 170 PS, Diesel)

VW Scirocco III (137, 138) (Year of Construction 08.2008 - 11.2017, 140 - 170 PS, Diesel)

VW Sharan I (7M8, 7M9, 7M6) (Year of Construction 09.1995 - 03.2010, 90 - 140 PS, Diesel)

VW Tiguan I (5N) (Year of Construction 09.2007 - 07.2018, 136 - 170 PS, Diesel)

VW Touran I (1T1, 1T2) (Year of Construction 02.2003 - 05.2010, 136 - 170 PS, Diesel)

Construction

A typical water pump consists of:

- Housing: Usually made of cast aluminum or iron, which encases the internal components and mounts to the engine.

- Impeller: A rotating component with blades that moves coolant through the system by centrifugal force.

- Shaft and Bearing Assembly: Connects the impeller to the drive pulley and allows it to spin smoothly.

- Seal: Prevents coolant from leaking out of the pump housing along the shaft.

- Pulley: Driven by the engine’s serpentine belt, timing belt, or timing chain, which powers the pump.

 

Operation

1. Coolant Circulation: As the engine runs, the water pump impeller rotates, driven by the engine’s belt or chain. The impeller blades push coolant from the radiator into the engine block and cylinder head.

2. Heat Transfer: Coolant absorbs heat from the engine as it circulates through the water jackets surrounding the cylinders and other engine components.

3. Return to Radiator: Heated coolant returns to the radiator, where it releases heat into the air passing through the radiator fins. The cooled coolant then returns to the water pump to repeat the cycle.

 

Importance

- Engine Cooling: The water pump is crucial for preventing engine overheating by ensuring continuous coolant flow.

- Engine Performance: By maintaining optimal operating temperatures, the water pump helps ensure efficient combustion and optimal engine performance.

- Longevity: Proper cooling extends the lifespan of engine components by preventing thermal damage and reducing wear and tear.

 

Maintenance

Regular maintenance and inspection of the water pump and cooling system are essential. Signs of a faulty water pump include:

- Overheating: The engine temperature rises excessively, indicating inadequate coolant circulation.

- Coolant Leaks: Visible coolant leaks around the water pump area, often caused by a failed seal or gasket.

- Noise: Unusual whining or grinding noises from the pump, suggesting worn bearings.

- Steam: Steam coming from the engine compartment, often a sign of overheating or a coolant leak.

 

Replacement

If the water pump fails, it should be replaced promptly to avoid severe engine damage. The replacement process generally involves:

1. Cooling the Engine: Ensure the engine and coolant are completely cool.

2. Draining Coolant: Drain the coolant from the radiator to prevent spillage during the pump replacement.

3. Removing Components: Remove any components obstructing access to the water pump, such as the fan, belts, or timing cover.

4. Removing the Old Pump: Unbolt and remove the faulty water pump.

5. Installing the New Pump: Install the new water pump with a new gasket or seal, and reassemble any removed components.

6. Refilling Coolant: Refill the cooling system with fresh coolant, bleed any air from the system, and check for leaks.

7. Testing: Start the engine and monitor the temperature and coolant flow to ensure the new pump is functioning correctly.

 

In summary, the water pump is a vital component that ensures efficient coolant circulation, maintaining engine temperature and performance. Regular inspection and timely replacement of a faulty water pump are essential to prevent overheating and extend engine life.