How to judge whether the valve oil seal of an automobile is broken and causes oil burning?

The oil burning of the valve oil seal can be judged by refueling the valve and releasing the throttle. If the exhaust gas is thick blue smoke, it means that the vehicle has burned engine oil. If the blue smoke disappears after hot car, this oil belongs to cold car oil.

This is due to the aging or damage of the valve oil seal, which leads to poor sealing effect and oil entering the cylinder from the valve. Burning engine oil means that the engine oil enters the combustion chamber of the engine and participates in the combustion together with the mixed gas, resulting in the rapid loss of engine oil and oil leakage. The most common problems that cause oil combustion are valve oil seal and piston ring.

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In the free state, the inner diameter of the oil seal lip is smaller than the shaft diameter, and there is a certain amount of interference.

After installation, the interference pressure of the oil seal cutting edge and the contraction force of the self-tightening spring produce radial pressure on the rotating shaft.

When the machine works, the lip of the oil seal will form a sealing contact ring of 0.25-0.5 mm under radial pressure. Under the internal lubricating oil pressure, part of the oil will penetrate between the oil seal cutting edge and the shaft, forming an extremely thin oil film. Under the surface tension of oil, the oil film will form a crescent surface between the rotating shaft and the cutting edge of the oil seal to prevent oil from overflowing, thus achieving the sealing effect.

Baidu encyclopedia-valve oil seal

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