Reasons for the Ticking Sound from the Chassis After Parking

[CharlesFitz]

After prolonged driving, the temperature of the exhaust system can become very high, especially the three-way catalytic converter, which typically operates at temperatures between 400-800 degrees Celsius. When the car is parked and rapidly cools down, thermal expansion and contraction occur, resulting in the "ticking" sound. Below are some related explanations: 1. Ticking sound during cold starts: When the car is cold-started, a ticking noise can often be heard from the engine compartment. This sound is caused by the oil pump not yet fully building up oil pressure during the cold start, leading to insufficient lubrication of the components. Normally, this ticking noise will disappear after the engine has been running for a while. 2. Three-way catalytic converter: The three-way catalytic converter is the most important external purification device installed in the car's exhaust system. It converts harmful gases such as CO, HC, and NOx emitted from the car's exhaust into harmless carbon dioxide, water, and nitrogen through oxidation and reduction reactions.