Fault Description:
The primary cause of elevated oil levels is the ingress of coolant, fuel, or hydraulic fluid into the engine oil.
Fault Diagnosis and Rectification
(1) Prior to starting, inspect the oil level height. Should the level appear elevated, loosen the oil drain plug on the sump to check for water in the discharged fluid. If the oil appears milky white after engine operation, indicating water ingress, inspect cylinder liners, water seals, water plugs, cylinder heads, and cylinder head gaskets for damage.
(2) With the engine running, open the radiator cap to observe whether the circulating water contains excessive bubbles or oil contamination. Oil ingress may indicate a damaged cylinder head gasket, while significant oil contamination suggests a faulty oil cooler.
(3) Check whether the engine oil has been diluted. If the oil smells of diesel, inspect the high-pressure fuel pump and delivery pump for diesel leaks. If oil is being expelled from the exhaust pipe, check whether individual cylinders are failing to operate or if the injectors are damaged.
(4) Check whether the hydraulic system oil level has dropped. If so, inspect the hydraulic pump for oil leakage from the shaft end oil seal.