What Causes the Abnormal Noise in Nissan Sylphy's Engine?
2 Answers
Engine abnormal noise can be caused by engine misfire, improper oil usage, timing belt noise, insufficient car warm-up time, and other factors. Below are some relevant introductions about the engine: Relatively small friction torque: The engine's valve drive mechanism adopts a hydraulic support roller rocker arm structure. Compared to the hydraulic tappet valve drive mechanism commonly used in current gasoline engines, this novel valve drive mechanism has the advantage of relatively small friction torque. Reduced camshaft weight: By using a hot-pressed camshaft, not only can the camshaft weight be reduced compared to the original one, but the engine can also achieve higher cam profile accuracy and more precise valve timing.
Last time I helped someone fix a Nissan Sylphy, I encountered an engine noise issue that sounded like a ticking or squeaking noise, possibly coming from several areas. The most common culprit is the belt system, such as a loose or worn-out timing belt, which can produce a harsh sound, especially noticeable during cold starts. Another possibility is engine bearing problems, like worn camshaft or crankshaft bearings, which can cause knocking sounds—this is related to engine oil. If the oil is too old or the oil pressure is insufficient, the lubrication effect worsens, accelerating wear. A faulty water pump can also produce a squeaking noise, as can abnormal airflow sounds caused by a clogged intake carbon canister. The Nissan Sylphy is a Japanese car with relatively reliable design, but carbon buildup and belt aging are common in vehicles over five years old. Don’t ignore this issue—untreated engine noise can worsen internal component damage and even lead to breakdowns. I recommend first checking the oil condition and belt tension, then visiting a professional repair shop to scan for trouble codes with a diagnostic tool. They can accurately pinpoint the source of the problem. Remember, replacing parts with new ones is often cheaper and safer than repairing old components.
