What are the symptoms of poor engine valve sealing?
2 Answers
Symptoms of poor engine valve sealing include: 1. Vehicle shaking and failure to start; 2. Decreased cylinder pressure, incomplete combustion, leading to carbon buildup; 3. Accelerated wear of pistons and cylinder liners. Causes of poor engine valve sealing are: 1. Insufficient valve clearance; 2. Excessive carbon deposits on the contact surface; 3. Deformation of the valve seat, valve tip, or rocker arm; 4. Spring failure. The function of the valve is to specifically input air into the engine and expel exhaust gases after combustion. Based on engine structure, valves are categorized into: 1. Intake valve: Draws air into the engine to mix with fuel for combustion; 2. Exhaust valve: Expels combustion exhaust gases and dissipates heat.
I've experienced the issue of engine valve leakage before. The most obvious symptom is difficulty during cold starts – it takes three or four cranks to get the engine going in the morning. At idle, the steering wheel shakes like a massage chair, and the RPM needle dances up and down. When driving on the highway, acceleration feels sluggish; even flooring the gas pedal doesn't provide much power, especially noticeable when going uphill. The sudden spike in fuel consumption is the most frustrating part – the same route now burns one-third more fuel. The exhaust pipe may backfire with popping sounds or emit black smoke, and if you listen carefully, you can hear a hissing air leakage sound from the engine. When these symptoms appear, there's an 80% chance it's a valve sealing problem that needs immediate repair, otherwise, the piston rings will suffer collateral damage.
