Buick Roadmaster Headlight Bulb Size

The Buick Roadmaster high beam and low beam headlight bulb sizes include 9004, H5001, H6024, and H5006 options, with each bulb size corresponding to specific vehicle configurations. The replacement chart covers 1950 to 1991 production years and details the bulb specifications for each model year.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

High Beam Headlight

Years	Bulb Size
1991	9004
1958	H5001
1954-1957	H6024
1950-1953	H6006

Low Beam Headlight

Years	Bulb Size
1991	9004
1958	H5006
1954-1957	H6024
1950-1953	H6006

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament halogen bulb with P29t base. 12V, 65W/45W.	9004
ANSI standard (US & Canada). 4-inch square sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H5001
ANSI standard (US & Canada). 7-inch round sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H6024
ANSI standard (US & Canada). 5x7-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H6006
ANSI standard (US & Canada). 5.75-inch round sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H5006

Other Locations

Additional Notes

The H6024 is a 7-inch round sealed beam unit operating at 12V. It functions as both the high beam and low beam headlight on the Buick Roadmaster for model years 1954-1957, meaning a single unit type serves both lighting functions in those years.
The H6006 is a 5x7-inch rectangular sealed beam unit operating at 12V. It appears across both the high beam and low beam positions for the 1950-1953 Roadmaster, again with one unit type covering both functions.
Sealed beam units such as the H6024, H6006, H5001, and H5006 are not replaceable bulbs in the conventional sense. When a sealed beam fails, the entire housing unit is replaced rather than an internal filament or capsule.
The 1958 Roadmaster marks a split in headlight specifications, with the high beam using the H5001, a 4-inch square sealed beam unit, while the low beam uses the H5006, a 5.75-inch round sealed beam unit. These two positions require physically different units and are not interchangeable.
The 9004 is a dual-filament halogen bulb with a P29t base, rated at 12V with 65W on high beam and 45W on low beam. Unlike the sealed beam units used in earlier Roadmaster years, the 9004 is a replaceable capsule-style bulb.
The 1991 Roadmaster uses the 9004 for both high beam and low beam functions, with a single bulb type handling both outputs through its dual-filament design.
All bulb types listed across the Roadmaster specifications conform to ANSI standards applicable in the United States and Canada, indicating standardized fitment within that market region.
The H5001 and H5006 units used on the 1958 Roadmaster are not shared with any other model year in these specifications, making them distinct to that year's fitment requirements.