What's the abnormal noise in Tianzhu engine compartment?

According to what you said, the car rattled at low speed, which should be the whistle of the engine. The main reason is that there is carbon deposit on the top of the piston, because carbon deposit forms a hot surface with high strength. At this time, the fuel mixture gas entering the combustion chamber begins to spontaneously ignite due to carbon deposition before reaching the ignition stroke. Although this combustion phenomenon seems to be sufficient, it is spontaneous combustion and premature combustion. If combustion is not stipulated in the stroke, there will be a metallic sound when the piston collides with the cylinder wall, which is what we often call the piston rod, and its scientific name is knocking. There are four main factors that cause knocking: too much carbon deposit, too early ignition time, low speed and high grade, or adding low grade gasoline may cause such failures.

See more information about Nissan Teana:/Nissan Teana/