Close off a cylinder head opening with this Dorman cylinder head plug, part number 555-108. It is a direct-fit replacement for the 1985-1988 Chevrolet Spectrum and 1989 Geo Spectrum with the L4-1.5L engine. This steel cup expansion plug comes in a 5/8 in. size with a height of 0.220, and it is built to replicate the original plug's fit and function on the listed applications.
A cup expansion plug is driven into a machined bore, and the cup is designed to hold a tight seal against it. If the original plug has gone missing or given out from fatigue, this engine cylinder head plug is intended to take its place.
- Direct-fit replacement: designed to fit and work like the factory plug on the listed Chevrolet and Geo applications.
- Steel cup design: a cup-type plug made of steel, with a 0.633 in. closed-end diameter and a 0.642 in. open-end diameter.
- Quality materials: made from quality materials for reliable performance.
- Trusted support: backed by Dorman's product experts in the United States and more than a century of automotive experience.
Signs this plug may need replacing include seepage around the plug, visible corrosion on the cup, or a plug that has loosened or gone missing. Diagnose the source of any leak before replacing parts. The listed applications use one plug, and the package contains one cup-type plug. Country of origin: United States.
Interchange: EPC212-25 · EPC282-25
EPC21225 · EPC28225
Frequently Asked Questions
Does this Dorman 555-108 plug fit the 1989 Geo Spectrum?
Yes, the 1989 Geo Spectrum with the L4-1.5L engine is a listed application. Check the "Vehicles it fits" section to confirm the fit for your vehicle.
What does a cylinder head plug do?
It is a steel cup expansion plug that closes off an opening in the cylinder head. It is driven into the bore, where the cup is designed to hold a tight seal.
What size is the Dorman 555-108?
It is listed as a 5/8 in. plug with a height of 0.220, a 0.633 in. closed-end diameter and a 0.642 in. open-end diameter.
What comes in the package?
The package contains one steel cup-type expansion plug.
How is a cup expansion plug installed?
Cup plugs are driven into a clean, undamaged bore rather than bolted in. Follow the vehicle service information for bore preparation, seating depth and whether sealant is needed.
