What causes air leakage at one corner of the screw on the three-way catalytic converter gasket?
2 Answers
Air leakage at one corner of the screw on the three-way catalytic converter gasket may be caused by the screw not being tightened properly or the screw being damaged. Below is relevant information about the automotive three-way catalytic converter: 1. Working principle: When high-temperature exhaust gases pass through the purification device, the purifying agent in the three-way catalytic converter enhances the activity of CO, HC, and NOx gases, promoting certain oxidation-reduction chemical reactions. CO oxidizes into colorless, non-toxic carbon dioxide gas at high temperatures; HC compounds oxidize into water (H2O) and carbon dioxide; NOx reduces into nitrogen and oxygen. 2. Consequences of damage: If the three-way catalytic converter is damaged, the secondary oxygen sensor on it will not be able to correctly provide data to the engine control unit, leading to either excessively lean or rich air-fuel mixture. A lean mixture can cause ignition difficulties, lack of power, engine backfiring, etc., while a rich mixture can increase fuel consumption, incomplete combustion, severe carbon deposits in the cylinders and spark plugs, etc. The engine fault light should illuminate when such faults occur.
I've encountered a similar situation before. Last time when I was repairing my car, I found that the screw at one corner of the catalytic converter gasket was leaking. This usually happens because the screw wasn't tightened properly or the gasket has aged and deformed. Think about it - the exhaust pipe operates at high temperatures, and thermal expansion and contraction can loosen the screws, especially at corner positions where the stress is greater. If the screws weren't tightened in a diagonal sequence with even force, one corner is more likely to lift and cause leaks. Another possibility is that the flange surface isn't flat and has deformed over time, resulting in poor sealing. If there's a leak, the exhaust sound will become noticeably louder, like a popping sound. I recommend first checking the screw torque, and if that doesn't work, replace the gasket. Remember to always work on a cold engine, otherwise there's a high risk of burns. When replacing the gasket, it's best to replace the screws as well - OEM parts tend to be more durable.
