Will the engine make a rattling noise when low on oil?

[SanAlivia]

Yes, the engine will make a rattling noise when low on oil. Here are the reasons for abnormal engine noises: 1. Valve noise: After starting the engine, you may hear a "tapping" sound, which is the sound of the valves, especially when the engine is cold. This happens because the oil pressure hasn't built up yet, and the valves are not properly lubricated. The noise should go away after a short while. This situation is common after the car has been parked for a long time. 2. Insufficient lubrication: Generally, during a cold start, the engine noise is slightly louder than when the engine is warm. As long as the sound is uniform and smooth, not harsh, there is usually no problem. This is because when the engine is cold, the gap between the cylinder wall and the piston has not yet reached the optimal size, and the oil lubrication is not sufficient. Normally, when the engine block temperature reaches about 95 degrees, the sound will return to normal. 3. Oil-related issues: Using low-quality oil, not changing the oil for a long time, or being low on oil can all increase friction between the valves and guides, as well as the hydraulic lifters, making various engine noises louder.