A beverage distribution center reported that a Heli CPCD30 forklift (Isuzu 4LE2 engine) emitted thick, continuous white smoke from the exhaust immediately upon startup. The engine idled roughly, misfiring noticeably. Once warm, the idle smoothed out, but the white smoke persisted, and the coolant reservoir was consistently overflowing.
The technician first ruled out fuel contamination. The white smoke had a distinctly sweet smell, pointing directly to coolant entering the combustion chamber. He performed a cylinder leak-down test. Cylinder #3 showed 25% leakage, and when he cranked the engine with the radiator cap off, coolant bubbled violently out of the radiator neck, confirming a compression-to-coolant leak.
He removed the cylinder head, expecting a blown head gasket. The head gasket appeared intact. However, when he removed the fuel injectors from the head, he found the "Injector Copper Washer" on Cylinder #3 was blown out and partially melted. The copper washer seals the injector face against the cylinder head to prevent combustion gases from escaping around the injector. The washer had failed due to incorrect torque during a previous injector service, combined with normal carbon erosion.
When the washer blew, high-pressure combustion gases (up to 1500°C) were forced directly into the cooling jacket surrounding the injector bore. During the intake stroke, the cylinder vacuum drew coolant from the jacket into the cylinder, causing the misfire and white smoke. On the compression stroke, the combustion pressure was forced back into the cooling system, causing the reservoir to overflow. The continuous coolant ingestion had also emulsified the engine oil, threatening bearing failure.
The repair involved thoroughly cleaning the injector bore in the cylinder head to remove all carbon and debris. A new OEM copper injector washer was installed, and the injector was torqued to specification using a three-stage sequence. The cylinder head was reinstalled with a new head gasket. The engine oil and filter were changed twice to flush the emulsified oil. After reassembly, the white smoke cleared immediately, the idle smoothed out, and the coolant system maintained normal pressure.
