Dorman 579-020 Fuel Tank Sending Unit Lock Ring

Fuel Tank Sending Unit Lock Ring for GM Applications

The Dorman 579-020 fuel tank sending unit lock ring secures the fuel pump and sending unit assembly to the tank opening. It is a metal replacement ring with a gasket/seal included, making it a practical choice when servicing the sending unit on select Buick, Chevrolet, Oldsmobile, and Pontiac vehicles.

• Metal construction for durable service
• Inside diameter: 1.875 in.
• Outside diameter: 4.25 in.
• Lock ring diameter: 3.625 in.
• Gasket or seal included
• Compatible with select GM fuel tank sending unit service applications

Detailed Product Overview

Dorman 579-020 is a fuel tank sending unit lock ring designed to retain the fuel pump assembly at the tank lock opening. It is recommended for replacement whenever the sending unit is serviced, helping restore a secure fit at the tank interface. This part cross-references Spectra Premium LO20 for the same application. Common fitment includes 1988-1997 Oldsmobile Cutlass Supreme, 1988-1996 Buick Regal, 1990-1996 Chevrolet Lumina, 1995-1996 Chevrolet Monte Carlo, and 1988-1996 Pontiac Grand Prix.

Common Issues This Part Addresses

• Loose or damaged fuel pump retaining ring
• Fuel tank sending unit service after removal
• Improper sealing at the tank opening
• Corrosion or wear on the original lock ring
• Need for a direct replacement during fuel system repair

Installation Notes and Tips

Verify the lock ring diameter and tank opening dimensions before installation. Clean the sealing surface thoroughly and inspect the gasket area for debris or damage before securing the sending unit. This part is used on select GM vehicles, including Buick Regal, Chevrolet Lumina, Oldsmobile Cutlass Supreme, Chevrolet Monte Carlo, and Pontiac Grand Prix, so confirm year and model match the vehicle before service.

Quality Assurance

Dorman manufactures this lock ring from metal for reliable service in fuel tank applications. The included gasket/seal supports a proper service replacement when the sending unit is removed and reinstalled.