Notes regarding the coolant pump - ra20006010215x(0215)

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

Engines 601, 602 (except 602.98), 603

General

The coolant pump located at the bottom right of the engine is attached to a light alloy housing bolted to the crankcase. The coolant thermostat (318) is likewise contained in this housing.

A flange (302) is pressed onto the coolant pump shaft (303) for attaching the belt pulley. The deformation space (E) is located between coolant pump bearing (304) and cassette seal (305). The fan is attached at the stub end (arrow).

Fig 1: Identifying Coolant Pump Components

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Engine 601

Arrangement of magnetic fan coupling and coolant pump

Fig 2: Identifying Coolant Pump Components - Engine 601

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Engines 601 (only in model 124), 602 and 603

Arrangement of viscous fan coupling and coolant pump

Fig 3: Identifying Coolant Pump Components - Engines 601 (Only In Model 124), 602 And 603

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Engine 601 in model 202

On this engine the viscous fan coupling is bolted onto the coolant pump mount by a union nut with left-hand thread.

Engine 601 in model 202

Fig 4: Identifying Coolant Pump Components - Engine 601 In Model 202

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Arrangement of viscous fan coupling and coolant pump

Coolant pump with drainage pipe

Since 01/92 coolant pumps with a drainage pipe (1) have been installed. This channels off any coolant which may flow out occasionally from the vent hole in the coolant pump housing. This thus eliminates any residue smears in the directly visible area. The coolant pump should only be replaced if coolant is found in the expansion tank as result of a leak in the coolant pump.

Coolant pumps for installation of drainage pipes are supplied through the parts sector. When installing, always install or replace the drainage pipe at the same time.

The drainage pipe can also be retrofitted. See Programmed Repairs for operation instructions.

Fig 5: Identifying Drainage Pipe

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The coolant pump of engines 602, 603 as of start of production, of 601 in model 124 as of 02/92, is strengthened at the coolant pump housing (301) and at the coolant pump bearing (304) because of the heavier viscous fan coupling.

The diameter of the impeller (306) on all the engines is identical.

The coolant pump shaft has a tapped hole M10 X 22 at the front for attaching the viscous fan coupling.

From 06/89 up to 11/88 a plastic impeller was fitted to engines 601.911/912.

Fig 6: Identifying Coolant Pump Components

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Engine 603.971

Since 09/95 a coolant pump with a larger impeller has been installed in this engine. This increases the volume flow in the cooling system.

Previous impeller Ø 68 mm

Present impeller Ø 72 mm