Diesel Geeks in Santee is a veteran-owned diesel truck repair and fabrication shop that opened on Railroad Avenue in 2024, staffed by technicians with more than 30 years of combined diesel-specific experience. The shop's custom welding and fabrication services produce heavy-gauge bumpers, bed-rack systems, and skid plates, while collision-damaged rigs requiring structural body repair route to Lloyd's Collision & Paint Center on Mission Gorge Road. Engine diagnostics cover Cummins, Duramax, and Power Stroke platforms using manufacturer-level scan tools to isolate turbo, injector, and emissions-system faults. Fleet contracts receive scheduled preventive-maintenance plans, multi-vehicle inspection rotations, and priority bay access to minimize commercial downtime. Routine maintenance items including oil changes, fuel-filter swaps, and coolant flushes complement the heavy repair side, covering the same fluid-service category that East County Lube Center provides for gasoline vehicles on Mission Gorge Road. All labor carries a 90-day warranty, and highest-tier services include diesel particulate filter regeneration-cycle diagnostics, exhaust gas recirculation system servicing, and turbocharger cartridge rebuild-and-balance procedures.