High Performance Ignition Coil for Hummer H3 H3T (2008-2010) 5.3L

Upgraded High Performance Ignition Coils for 2008-2010 Hummer H3 (5.3L LH8/LH9 / GMT345)

What it Does: Delivers a stronger, more consistent spark to the combustion chamber, replacing degraded factory coils to cure misfires and restore throttle response on high-mileage V8 platforms.

The Stock GM GMT345 Ignition Coil Degradation

Factory GM ignition coils on the 5.3L LH8 and LH9 platforms are subjected to extreme thermal cycling within the engine bay, particularly when operating under heavy load during off-road articulation or towing. Over time, the OEM dielectric epoxy degrades, leading to internal voltage leaks. This thermal breakdown compromises the magnetic field generation within the primary and secondary windings. The resulting weak spark causes intermittent misfires under load, hesitation during acceleration, reduced fuel economy, and eventual P0300-series diagnostic trouble codes. Furthermore, the OEM rubber boots become brittle and fail to maintain a proper seal against the spark plug ceramic, allowing moisture intrusion and arcing.

The Engineering Solution

These replacement UF414 ignition coils are engineered to exceed OEM specifications, directly addressing the thermal limitations of the factory units. Utilizing high-temperature resistant epoxy vacuum-sealed within the coil housing, these upgraded units eliminate internal air pockets that cause premature insulation breakdown. The primary and secondary copper windings feature a specialized enamel coating and optimized turn ratios to output a hotter, faster-charging spark. This translates to complete fuel burn during the power stroke, mitigating carbon fouling and restoring torque delivery. Additionally, the pre-greased, heat-resistant silicone boots provide superior dielectric isolation and a weather-tight seal against the spark plug, ensuring maximum voltage transfer even in demanding environments.

Technical Specifications

Compatibility

• 2008 Hummer H3 5.3L V8 (Alpha)
• 2009 Hummer H3 5.3L V8 (Alpha)
• 2009 Hummer H3T 5.3L V8 (Alpha)
• 2010 Hummer H3 5.3L V8 (Alpha)
• 2010 Hummer H3T 5.3L V8 (Alpha)

The Hummer Durability Standard

For a 4x4 built for overland travel and utility, drivetrain reliability is mandatory. Upgrading to these reinforced ignition coils ensures steady power delivery, optimal fuel efficiency, and dependable performance whether navigating rock-crawling trails or hauling heavy payloads.