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Index

Model

Chassis

Engine

Transmission

E350

R350

S550

W251

W212

W221

M276

722.9

M278

Mercedes-Benz

Coolant Pump Replace (M276)

Brand: Mercedes-Benz

Model: R350

Chassis: W251

​Engine: M276 DE35

Transmission: 722.9

Project: Repair

​Labor: 3 hours

Overview

The vehicle's engine water pump is responsible for keeping coolant flowing through the engine. As water pumps get old the internal bearing can go bad causing noise and a coolant leak. A good indicator that your water pump is failing is if you see coolant leaking through the water pump "weep hole".

​

Engine Water Pump Failure Symptoms

  • Coolant leak through weep hole

  • Play at water pump pulley shaft indicating a bad bearing

  • Squeaking noise coming from the pump at idle

  • Overheating conditions

  • Low coolant light on instrument cluster indicating a cooling system leak

Parts & Accessories

Coolant Pump: A 276 200 04 01 (engine no. up to 30022368)

                          A 276 200 13 01  (​engine no. up to 30022368)

                          Check Engine Number

Coolant: Genuine Mercedes Q1030004

               Antifreeze/water=50/50, up to -37°C

               Antifreeze/water=55/45, up to -45°C

Tools

Remove

Step 1  Open The Engine Hood

Substep

1.1 Pull lever (1) in the left side of the footwell to unlock the engine hood (2) Engine hood jumps open; lift engine hood slightly if necessary

1.2 Raise handle (3) and open engine hood. Windshield wiper arms must not be folded forward;​

1.3 Press the red release button (4) on the gas-operated strut and position the engine hood vertically.

Step 2 Lift Vehicle

Substep:

2.1 Jack front vehicle at front central jack point;

2.2 Support vehicle at front side jack points with jack stands;

2.3 Jack rear vehicle at rear central jack point, if w/o rear central jack point, jack at the bottom of differential sell which  fixed at subframe carrier directly;

2.4 Support vehicle at rear side jack points with jack stands.

Step 3 Remove bottom engine compartment paneling

Substep:

3.1 Remove bolts (4) (8 bolts).​

3.2 Remove rear engine compartment paneling (2) Do not lose washers(5) When installing ensure the washer(5) is seated correctly

3.3 Remove bolt (3) (6 bolts).​

3.4 Remove front engine compartment paneling (1)

Step 4 Drain Coolant from Radiator