Dorman

Dorman 555-052 Engine Expansion Plug

Brand Dorman 555-052
Describe Type Cup Type
Material Steel
Maximum Diameter 2.264
Minimum Diameter 2.251
Package Contents Expansion Plug
Fits Buick, Oldsmobile, and Pontiac · 33 vehicles

OE direct replacement. Matches the fit and function of the original engine expansion plug.

Steel construction. Built from quality material for reliable performance.

Cup type design. Engine core plug for sealing engine block openings.

Cross-references 31580, 1343487 and EPC-81 for the same application. See all 3.

$33.69Free shipping
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Dorman 555-052 Engine Expansion Plug

Dorman 555-052 is a steel cup-type engine expansion plug built to match the fit and function of the original engine core plug on specified Buick, Oldsmobile, and Pontiac applications. Its 2.251 to 2.264 diameter range supports a precise seal in the engine block opening.

Use this engine core plug when servicing classic GM engines that require a steel replacement plug with OE-style dimensions. The Dorman 555-052 is a direct-fit solution for restoration work and engine repair on select Buick Skylark, Buick LeSabre, Buick Riviera, Buick Century, Buick Roadmaster, Oldsmobile Cutlass, and Pontiac Tempest applications.

Key Features

  • Steel construction for engine block sealing applications
  • Cup-type expansion plug design
  • Maximum diameter: 2.264
  • Minimum diameter: 2.251
  • Matches the fit and function of the original engine core plug
  • Cross-reference part numbers include 31580 and EPC-81

Detailed Description

This Dorman engine expansion plug is engineered for specified vehicles where a steel cup-type core plug is required. It is used in engine hardware applications to close block openings and maintain proper sealing in the cooling system area. For restorations and repairs on 1950s and 1960s GM engines, part number 555-052 provides the correct style and dimensions for a dependable replacement.

Fits 1954 Buick Skylark, N/A. Fits 1959-1965 Buick LeSabre, N/A. Fits 1963-1965 Buick Riviera, N/A. Fits 1954-1958 Buick Century, N/A. Fits 1953-1958 Buick Roadmaster, N/A. Fits 1962-1963 Oldsmobile Cutlass, N/A. Fits 1961-1962 Pontiac Tempest, N/A. Fits 1964-1967 Buick Skylark, N/A.

This part cross-references 31580 and EPC-81 for the same application.

Common Uses

  • Replacing a leaking or corroded engine core plug
  • Restoring proper sealing in a rebuilt engine block
  • Servicing classic Buick, Oldsmobile, and Pontiac cooling system openings
  • Addressing engine block seepage around worn expansion plug bores

Installation Notes and Tips

Verify the block opening diameter before installation and confirm the plug’s cup-type profile matches the original part. Clean the bore thoroughly so the steel plug seats evenly, and follow the vehicle service procedure for proper installation depth and sealing.

Quality Assurance

Dorman designs this engine expansion plug to match original part fit and function on specified vehicles and manufactures it from quality materials for reliable performance.

This part fits 33 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelLitersCylindersPositionNotes
1967BuickSkylark4.9LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1966BuickSkylark4.9LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1966BuickSkylark6.6LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1965BuickLeSabreN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1965BuickRiviera6.6LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1965BuickSkylark4.9LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1965BuickSkylark6.6LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1964BuickLeSabre4.9LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1964BuickLeSabre6.6LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1964BuickRiviera6.6LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1964BuickSkylark4.9LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1963BuickLeSabreN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1963BuickRiviera6.6LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1963OldsmobileCutlass3.5LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1962BuickLeSabreN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1962OldsmobileCutlass3.5LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1962PontiacTempest3.5LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1961BuickLeSabreN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1961PontiacTempest3.5LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1960BuickLeSabreN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1959BuickLeSabre6.0LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1958BuickCenturyN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1958BuickRoadmasterN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1957BuickCenturyN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1957BuickRoadmasterN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1956BuickCenturyN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1956BuickRoadmasterN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1955BuickCenturyN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1955BuickRoadmasterN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1954BuickCenturyN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1954BuickRoadmasterN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1954BuickSkylark5.3LV8N/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
1953BuickRoadmasterN/ASteel; 4 Required, Package Quantity: 10, Boxed Packaging Type
Directly replaces or cross-references 3 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
315801343487EPC-81