Fault Description:
White smoke from the exhaust is caused by unburned diesel vapour within the combustion chamber or the ingress of coolant into the combustion chamber.
Diagnosis and Rectification Methods:
(1) With the diesel engine running, loosen the bleed screw on the injection pump or the high-pressure fuel line fitting. Inspect the fuel flow for water droplets. If water droplets are present, this indicates that the cause of white smoke from the exhaust pipe is water in the diesel fuel. Thoroughly drain water from the fuel tank, diesel filter, and both high- and low-pressure fuel lines.
(2) If no water is present in the diesel, open the radiator cap and observe for bubbles rising within the radiator. Bubble formation indicates coolant ingress into the cylinders. Remove the cylinder head to locate the fault, then repair or replace components as necessary.
(3) If no water has entered the cylinder, check the cylinder pressure. Should the pressure be excessively low, undertake repairs.
(4) During winter operation, frequent operation of the diesel engine at low temperatures may also cause white smoke from the exhaust pipe.
(5) If none of the above issues are present, inspect the spray pattern quality of the injectors.
(6) If spray pattern meets specifications, verify fuel injection timing and adjust as required. Poor-quality diesel fuel may also contribute to white smoke from the exhaust pipe. Where necessary, replace with fresh fuel for comparative testing.