Why is the car consuming engine oil quickly without emitting blue smoke?

[StDallas]

Rapid engine oil consumption without blue smoke emission is mainly caused by the following reasons: 1. Deterioration of the valve stem seals' sealing performance can lead to oil burning. Valve stem seals are made of rubber and can harden over time due to prolonged exposure to high temperatures. Hardened seals lose their sealing effectiveness, allowing oil to flow through the valve guides into the combustion chamber, resulting in oil burning. 2. Malfunction of the piston rings in the engine can also cause oil burning. When piston rings wear to a certain extent, they fail to completely scrape oil off the cylinder walls, leaving residual oil that leads to oil burning. 3. Failure of the engine's external oil separator can also result in oil burning. The oil separator is responsible for separating blow-by gases and oil vapor in the crankcase. If it malfunctions, it cannot fully separate oil vapor, causing some oil vapor to be recirculated into the combustion chamber and burned. 4. Design flaws in the crankcase can lead to oil burning. Normal oil burning typically does not produce blue smoke; only severe oil burning will cause blue smoke emissions from the exhaust.