Oldsmobile Custom Cruiser Headlight Bulb Size

Additional Notes

• The Oldsmobile Custom Cruiser uses three distinct headlight technologies across its production span: sealed beam units in rectangular and round form factors, and a dual-filament halogen bulb introduced in the 1991-1992 model years.
• The 9004 is a dual-filament halogen bulb rated at 12V with a 65W high beam filament and a 45W low beam filament, mounted on a P29t base. Because both filaments are housed in a single bulb, one 9004 unit serves both the high and low beam functions on the 1991-1992 Custom Cruiser.
• The H4651, H4652, and H4656 are all 4x6-inch rectangular sealed beam units operating at 12V. The H4652 is a variant of the H4651, and while the two share the same physical format, they are not interchangeable with each other or with the H4656 without confirming the correct beam pattern for the specific model year.
• The H5001 and H5006 are sealed beam units in a round form factor, both operating at 12V. The H5001 is a 4-inch square sealed beam used for the high beam, while the H5006 is a 5.75-inch round sealed beam used for the low beam on the 1971-1975 Custom Cruiser.
• All sealed beam types, including the H4651, H4652, H4656, H5001, and H5006, are self-contained units in which the lens, reflector, and filament form a single assembly. When the filament fails, the entire unit requires replacement rather than a bulb swap.
• The low beam specification for the Custom Cruiser varies across individual years even within the same general era. For example, the H4652 appears in 1977, 1981-1982, 1985, and 1989, while the H4656 is specified for surrounding years, making year-specific confirmation necessary before sourcing a replacement sealed beam.
• All bulb types listed across both high and low beam positions conform to ANSI standards applicable in the United States and Canada, indicating standardized fitment within that regulatory framework.
• The high beam position used the H4651 consistently across the 1976-1990 model years, representing the longest uninterrupted use of a single bulb type in the Custom Cruiser headlight specifications.