A logistics warehouse reported that a TCM FG25 (Nissan QD32 engine) forklift emitted heavy white smoke from the exhaust and was running rough. The operator also noted the engine oil level had risen above the "FULL" mark on the dipstick.
The technician immediately recognized that "rising oil level" indicates "Fuel Dilution." He pulled the dipstick; the oil smelled heavily of diesel. He performed a "Cylinder Cutout Test" by loosening the fuel injector lines one by one. Cylinders #2 and #3 showed no change in engine sound when loosened, indicating they were not firing.
He removed the fuel injectors for cylinders #2 and #3. The "Injector Nozzle Tips" were seized open by carbon buildup and sulfur deposits (from low-quality diesel). The nozzles were stuck in the "Spray" position. Instead of atomizing the fuel only during the combustion stroke, they were dripping raw diesel continuously into the cylinder. The diesel did not ignite (causing the white smoke) and instead washed past the piston rings into the crankcase, mixing with the oil.
The repair involved sending all four injectors to a specialist for "Ultrasonic Cleaning" and nozzle replacement. The engine oil and oil filter were drained and replaced. The fuel filter was replaced, and a fuel system cleaner additive was added. After reinstallation, the engine ran smoothly, the white smoke cleared, and the oil level stabilized.
