What Causes Abnormal Engine Noises When the Engine Oil Burns Out?
3 Answers
There are many reasons for abnormal engine noises when the engine oil burns out, including excessively high oil viscosity, improper timing belt tension, incomplete fuel combustion, exhaust system malfunctions, and cooling system issues. If abnormal engine noises occur, timely inspection and measures should be taken. Below is a detailed explanation of the causes of abnormal engine noises: 1. Unsuitable engine oil: If the oil viscosity is too high, it can lead to insufficient lubrication in the engine, causing friction. It is recommended that car owners choose the appropriate oil for their vehicles during maintenance to avoid this issue. 2. Timing belt noise: Insufficient tension in the timing belt can cause it to stretch excessively under prolonged use, resulting in abnormal noises. This requires adjustment of the timing belt tension at a repair shop or, in severe cases, replacement. 3. Incomplete fuel combustion: Using poor-quality fuel can prevent the engine from operating normally and efficiently. In such cases, it is necessary to refuel with high-quality gasoline.
After the engine oil burns out, the engine will indeed make strange noises, just like metal parts fighting each other. Many components inside the engine rely on oil for lubrication, such as the crankshaft and connecting rods. Without oil, they will experience direct dry friction, producing clanking and knocking sounds. In severe cases, the bearings can wear out directly, resulting in a rattling noise. I've personally seen such an engine disassembled, with the metal surfaces all scratched up. It's recommended to stop and check immediately when the oil light comes on, don't wait for the noise to appear before taking action. Normally, you should check the oil dipstick every thousand kilometers, as older cars are more prone to burning oil.
Engine knocking after burning off oil is very common, mainly due to loss of lubrication protection. When the engine is running, components like piston rings and camshafts experience high-speed friction every second. Once the oil burns out completely, there's no oil film separating the metal parts, resulting in direct metal-to-metal contact. At this point, you'll hear tapping or clicking sounds, typically coming from the mid-lower section of the engine. If you continue driving for a few more minutes, the sound turns into a rumbling noise - this is the precursor to cylinder scoring. I remember my friend's Lavida had this exact issue last time, costing over 8,000 yuan in repairs. Always check oil levels when the engine is cold using the dipstick - if it's near the lower mark, refill immediately.
