What Causes Loud Engine Noise in Nissan Sunny?
2 Answers
Nissan Sunny's loud engine noise is mainly caused by engine abnormal sound or insufficient engine oil. Solutions: Perform firewall sound insulation and engine hood sound insulation. The effect is relatively obvious, but the project is huge, the labor cost is expensive, so be mentally prepared. Only do engine hood sound insulation. It has an effect, but not as obvious as doing both firewall and engine hood sound insulation. Ensure the engine is normal. Check the engine to confirm it is normal. If the engine is normal, change to good engine oil, then the engine noise will be reduced. Causes of engine abnormal sound: Loose screws on the lower guard plate, a relatively common minor fault, just tighten or adjust the screws of the engine lower guard plate. Aging of engine mount pads, engine mount pads support the engine, and can only be replaced after aging. Loose plastic parts, such as the engine hood plate, intake pipe, etc., just tighten them. Belt abnormal sound, including power steering belt, generator belt, etc., belt aging or being too loose or too tight will cause abnormal sound, replace or adjust the tightness. Engine knocking, excessive carbon deposits inside the engine or use of unqualified fuel, can clean carbon deposits and replace fuel.
My Nissan Sunny's engine was also unusually loud last year, making it quite noisy inside the car. Typically, such noise could be related to the engine oil—either it's old or the wrong type, leading to poor lubrication and causing the engine to roar. Another common issue is the belts; if the alternator belt or air conditioning belt is loose or worn, it can produce a sharp squealing sound, especially noticeable at higher RPMs. A leaking exhaust muffler is another culprit, resulting in a low-pitched rumble. Worn engine mounts that fail to dampen vibrations can also increase cabin noise. Some mention valve issues or piston ring wear, though these are less likely. I recommend first checking the engine oil: after warming up the car, pull out the dipstick—if the oil is black, change it immediately. Then, identify the noise source: sharp sounds from the front likely indicate belt issues, while a deep noise from the rear suggests exhaust problems. Safety first—prolonged loud noises accelerate part wear, so visit a repair shop early to avoid bigger risks. Regular maintenance, like oil changes every 5,000 km, significantly reduces noise issues.
