Firewall Gromment 4in OD 1-3/4in ID

The Firewall Grommet 4in OD 1-3/4in ID from SEALS-IT is an essential component for any serious engine bay modification or restoration project. Whether you're running new wiring harnesses, fuel lines, or brake lines through your firewall, this precision-engineered grommet seals the penetration while protecting your lines from sharp edges and engine heat. Mechanics and enthusiasts trust SEALS-IT grommets to maintain factory-quality integrity in custom builds, restorations, and performance upgrades where proper firewall sealing prevents water intrusion, pest entry, and electrical hazards.

Constructed from durable elastomer material, this grommet features a 4-inch outer diameter that sits flush against your firewall surface, with a 1-3/4-inch inner diameter opening to accommodate multiple small-gauge wiring bundles or fuel lines simultaneously. The design allows for secure passage while the rubber compound resists oil, coolant, and fuel exposure—critical for engine bay longevity. The compact 0.25-inch wall thickness provides structural support without excess bulk, and the grommet's molded profile ensures a tight seal that remains effective through thermal cycling and vibration over thousands of miles.

This firewall grommet suits street machines, hot rods, resto-mods, and production vehicles undergoing electrical or fuel system rewiring. Installation is straightforward—simply enlarge your firewall opening to 4 inches and press the grommet into place for a permanent seal. The SEALS-IT grommet (MPN GS40430) works with any aftermarket harness, custom fuel line routing, or brake line relocation where factory grommets don't match your modified engine bay layout. Weighing just 0.04 lbs, it's an overlooked detail that separates professional-grade builds from amateur work.