Keep old main and connecting rod bearings when doing an engine overhaul, then look at them to understand how well the engine ran. The reason bearings don't last is typically because of dirty oil, too much weight, or rust buildup. If we don't fix these problems before reinstalling the engine parts, they will break again. When you check bearings, take them off their current spots and set them down neat on a fresh surface to see where the crankshaft meets problems. Dirt particles can get into the engine during assembly, pass through filters, or come from machine tools, and these contaminants can hide in bearings and wreck them; you need to clean well and change oils often to stop this from happening. Failures happen when too much heat builds up, when bearings get overloaded, when oil leaks or passes block, or when friction destroys the bearing. When we drive fast but slowly, or make many short trips, these driving practices worsen bearing life because they deplete the oil film that keeps bearings from wearing out and create conditions for bearing corrosion to develop. Putting the parts in wrong during installation blocks clean oil from reaching the engine, which harms the engine when small pieces get trapped inside. When current bearings are bad or oil clearance is wrong, you must find new bearings that match, and check that they match the ground crankshaft size. Check the original color code of main bearings for standard size, and if not visible, search for stamped codes on the block to find correct parts. As with new bearings, you should check the connection between connecting rod caps and crankshaft through matching the code labels or by carefully reading the numbers stamped on them. Getting help from your dealer is necessary to pick the right bearing based on your oil clearance measurements.