What Causes Abnormal Noises When Starting the Car?
1 Answers
The reasons for abnormal noises when starting the car: 1. Worn hydraulic lifters or system pressure loss - Normally, hydraulic lifters maintain constant oil pressure to ensure zero valve clearance, preventing valve noise during operation; 2. Insufficient lubrication system pressure or severely worn hydraulic lifters - When internal pressure can't support the plunger, valve clearance increases, causing ticking valve impacts during engine operation; 3. Severely worn hydraulic lifters - After prolonged parking, oil leaks from hydraulic lifters, resulting in insufficient oil in hydraulic tappets during initial startup, producing tapping sounds from valve stem impacts.