what causes blue smoke from a diesel engine?

Diesel engines often emit smoke during work, which makes many drivers nervous.

If the experienced drivers encounter problems such as smoke from the engine, they can make fault diagnosis according to the troubleshooting methods given below.

Exhaust blue smoke

cause of issue

Blue smoke is mainly caused by excessive combustion of the engine oil, which is related to engine wear.

1.The engine is normally worn.

Due to the age of the engine, the wear between the working parts is intensified, resulting in a large gap and a decrease in sealing performance. The oil is sucked into the cylinder through other parts to participate in combustion, resulting in blue smoke.

2.The engine is abnormally worn.

As the engine is in use, the friction components are not fully lubricated (long-term lack of oil or no oil / flttraton change; large throttle operation in the engine cold state, etc.), causing abnormal abrasion, lead to oil leakage and combustion. Produce blue smoke.

Note: Poor oil can also cause blue smoke.


1.When the engine is started to emit blue smoke in the cold state, the engine needs to be disassembled to replace the valve oil seal. usually, the full set valve oil seal is replaced.

2.If the engine emits blue smoke when accelerating, it needs to be disassembled. The specific reason is that the gap between the piston and the cylinder is too large, or the piston ring is opposite. If the piston ring is opposite, adjust the opening position of the piston ring; if it is not correct, measure the gap between the piston and the cylinder, the end gap of the piston ring, and compare the measured value with the standard value provided by the engine manufacturer to determine whether it needs to be replaced with new parts.

3.The engine smokes a lot of blue smoke at any time. If the engine emits a large amount of blue smoke under any working conditions, it proves that the engine wear is already quite serious, and it must be overhauled. Otherwise, it is very likely that the engine will pull the cylinder, hold the bearing, and even cause the engine to be scrapped, resulting in more serious losses.



Contact: Wigo

Phone: 19922967201

Tel: 19922967201


Add: No. 70-19, Banshan First Village, Zhongliangshan Street, Jiulongpo Dist, Chongqing city,China.

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