What are the symptoms of damaged valve stem seals?

[Jason]

Symptoms of damaged valve stem seals: 1. The engine burns oil, emitting blue smoke; 2. Severe carbon buildup on spark plugs, resulting in reduced engine power; 3. Decreased sealing leading to insufficient cylinder pressure and reduced engine power; 4. Accelerated oil consumption, which in severe cases can directly cause engine seizure due to lubrication and cooling failure. Causes of valve stem seal damage: 1. During assembly, misalignment of threads or splines can cause oil leakage due to poor sealing, also damaging the seal itself; 2. The tightness of the spring not meeting technical requirements—too tight can cause improper fit between the seal and the rotating shaft, leading to abnormal wear, while too loose can result in insufficient pressure to seal properly.