Mack WS Headlight Bulb Size

Mack WS headlight bulb sizes include H6024, H4651, and H5001 for high beam applications, along with H6024, H4656, and H5006 for low beam configurations, with each bulb size corresponding to specific lighting functions. The replacement chart covers 1981 through 1984 vehicle production years and documents bulb size specifications for this model.

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
1981-1984	H6024 (With 2 Round Headlamps)
	H4651 (With 4 Rectangular Headlamps)
	H5001 (With 4 Round Headlamps)

Low Beam Headlight

Years	Bulb Size
1984	H6024 (With 2 Round Headlamps)
	H4656 (With 4 Rectangular Headlamps)
	H5006 (With 4 Round Headlamps)
1982-1983	H6024 (With 2 Round Headlamps)
	H4652 (With 4 Rectangular Headlamps)
	H5006 (With 4 Round Headlamps)
1981	H6024 (With 2 Round Headlamps)
	H4656 (With 4 Rectangular Headlamps)
	H5006 (With 4 Round Headlamps)

Bulb Specifications

Description	Bulb Size
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). 4x6-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H4651
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). 4x6-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H4656
ANSI standard (US & Canada). 5.75-inch round sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H5006
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit, variant of H4651. Not a replaceable bulb — the entire unit is replaced. 12V.	H4652

Other Locations

Additional Notes

All headlight bulb sizes specified for the Mack WS across the 1981-1984 model years are sealed beam units conforming to ANSI standards recognized in both the United States and Canada. Sealed beam construction means the lens, reflector, and filament are fused into a single glass unit, so the entire assembly is replaced rather than an internal bulb.
Three distinct headlamp configurations are documented across all four model years: a two-round-lamp arrangement, a four-rectangular-lamp arrangement, and a four-round-lamp arrangement. Each configuration uses a different set of bulb sizes, and fitment is not interchangeable between configurations.
The H6024 is a 7-inch round sealed beam unit operating at 12V. It serves as both the high beam and low beam in the two-round-lamp configuration, meaning a single unit type handles both functions in that setup across all documented years.
The four-round-lamp configuration uses the H5001 for high beam and the H5006 for low beam. The H5001 is a 4-inch square sealed beam unit, while the H5006 is a 5.75-inch round sealed beam unit, both rated at 12V. These two units are not interchangeable despite appearing in the same headlamp system.
The four-rectangular-lamp configuration uses 4x6-inch rectangular sealed beam units across all positions, but the specific variant differs by function and year. The H4651 covers the high beam position for all four years, while the low beam position uses the H4656 in 1981 and 1984, and the H4652 in 1982-1983.
The H4652 is documented as a variant of the H4651, both being 4x6-inch rectangular sealed beam units at 12V. Despite their physical similarity, they are designated for different beam positions and are not listed as interchangeable within these specifications.
The low beam rectangular fitment for the four-rectangular-lamp configuration is not uniform across the 1981-1984 range. The H4656 applies to 1981 and 1984, while the H4652 applies to 1982-1983, indicating that year of manufacture is a necessary factor when selecting a low beam replacement for that configuration.
All six bulb types covered in these specifications operate at 12V and share the same ANSI standardization framework, but their physical forms vary across three distinct sizes and shapes, making cross-type substitution incompatible regardless of shared electrical ratings.