The crankshaft main bearings are like the backbone of your engine’s smooth operation. They sit between the crankshaft and the engine block, keeping everything spinning freely without grinding or friction. When these bearings wear out, your car starts showing small but serious signs — a dull knocking noise, a sudden drop in oil pressure, or even tiny metal bits in the oil. These are red flags you shouldn’t ignore. Replacing main bearings at the right time can save you from a full engine rebuild later. Regular oil changes and using good-quality engine oil make a big difference in how long they last. Many car lovers say inspecting them during major tune-ups is the best preventive step. If you’re into DIY repairs, always check clearance and use proper torque settings when installing new bearings. A well-maintained set of crankshaft main bearings keeps your engine running quietly, smoothly, and strongly for years to come.