If your Daihatsu spark plugs are consistently getting soaked in engine oil and going bad, it indicates a potential problem with the engine's internal components or the spark plug seals. Here are a few possible reasons for this issue:
Worn Piston Rings: One possible cause is worn piston rings. If the piston rings are worn or damaged, they may allow engine oil to leak into the combustion chamber. As a result, the oil can come in contact with the spark plugs, causing them to become soaked and eventually fail.
Valve Stem Seals: Another potential cause is faulty valve stem seals. The valve stem seals are responsible for preventing engine oil from entering the combustion chamber through the valves. If these seals are worn or damaged, oil can seep past them and contaminate the spark plugs.
PCV System Issues: Problems with the Positive Crankcase Ventilation (PCV) system can also contribute to oil-soaked spark plugs. The PCV system is designed to remove blow-by gases and excess oil vapor from the crankcase. If the PCV valve or related components are malfunctioning or clogged, it can cause increased pressure inside the crankcase and result in oil being forced into the combustion chamber.
Overfilling Oil: Overfilling the engine with oil can cause excessive oil consumption and lead to oil leaking into the combustion chamber. This can cause the spark plugs to become fouled with oil.
To resolve the issue, it is recommended to have your Daihatsu vehicle inspected by a qualified mechanic. They can diagnose the specific cause of the oil leakage, whether it's worn piston rings, faulty valve stem seals, PCV system problems, or another issue. The necessary repairs or replacements can then be performed to prevent further oil contamination of the spark plugs and ensure proper engine operation.