What Causes the Rattling Noise When Accelerating in a Regal?
2 Answers
Here are the possible reasons for the rattling noise when accelerating in a Regal: 1. Valve Noise: After starting the engine, a 'ticking' sound is heard. This is the sound of the valves, especially noticeable when the engine is cold. It occurs because the oil pressure hasn't built up yet, and the valves aren't properly lubricated. The sound should disappear after a short while. This is common if the car has been parked for an extended period. If the sound persists, it could indicate excessive valve clearance or oil leakage at the camshaft, requiring valve clearance adjustment or replacement of relevant oil seals. Another possibility is the use of unsuitable engine oil, such as thinner oil in high-mileage vehicles. Changing the oil can resolve this issue (refer to 'How to Choose the Right Engine Oil' for guidance). 2. Engine 'Backfire' Issue: A 'popping' sound when decelerating or lifting off the throttle may indicate an engine 'backfire' issue, commonly referred to as engine 'backfiring.' Excessive carbon buildup on the valves or incorrect valve timing can cause this noise. Cleaning the valve carbon deposits or adjusting the valve timing may be necessary.
My Regal also experienced a rattling noise during acceleration. At first, I thought it was engine knock due to using cheap gasoline, where poor fuel quality caused abnormal combustion and noise. Later, I found out that a more common cause is issues with the hydraulic lifters or timing system—insufficient oil pressure or component wear can lead to noise when oil supply can't keep up during acceleration. Another possibility is a loose belt tensioner, which can cause a rattling sound when the belt slips. After I switched to premium gasoline and replaced the belt tensioner, the noise disappeared. I recommend you first check the fuel quality and belt condition, and refuel at reputable gas stations. If the noise persists for several days, take it to a repair shop immediately to avoid compromising driving safety or causing more serious damage.
