Metelli PA578 Engine Water Pump

Metelli PA578 Engine Water Pump

The Metelli PA578 engine water pump is a new replacement water pump built with an aluminum housing and a cast iron impeller for Mercedes-Benz applications. It includes a gasket for a cleaner service replacement and is specified for select 1990-1995 Mercedes-Benz E-Class, S-Class, and SL-Class models.

Key Features

• Brand: Metelli
• Part number: PA578
• New engine water pump
• Aluminum housing for corrosion-resistant construction
• Cast iron impeller with 8 vanes
• Ball/Ball bearing design
• Impeller outside diameter: 82
• Bearing outside diameter: 36
• Gasket included
• Package contents: water pump, gasket

Product Details

Metelli PA578 is an OE-style engine water pump for Mercedes-Benz cooling system service. The aluminum housing supports durable fitment, while the cast iron impeller and ball/bal bearing arrangement are selected for consistent coolant circulation and dependable operation. This part cross-references Gates 43168 for the same application. The PA578 is listed for 1990-1995 Mercedes-Benz 400E, 400SE, 400SEL, 500E, 500SEC, 500SEL, 500SL, E420, E500, S420, S500, and SL500, with engine-number-specific fitment on several models.

Common Problems This Part Addresses

• Coolant leakage from a worn water pump seal or housing
• Overheating caused by reduced coolant circulation
• Noise from worn pump bearings
• Impeller wear that limits coolant flow
• Cooling system service needs on Mercedes-Benz E-Class, S-Class, and SL-Class vehicles

Installation Notes and Tips

Verify engine-number fitment before ordering, since several applications are limited to specific engine ranges. Replace the gasket during installation and inspect the cooling system, belt drive, hoses, and thermostat for wear or contamination. Proper coolant fill and bleeding are important after installation to help prevent air pockets and temperature fluctuations.

Quality Assurance

Metelli supplies a new replacement water pump with the listed construction details and included gasket for the specified Mercedes-Benz applications. Confirm the part number PA578 and the engine-number notes against the vehicle before installation.