What are the causes of bearing seizure?
2 Answers
The causes of bearing seizure are: 1. Poor quality of the crankshaft and bearings, with insufficient smoothness of the journal and bearing surfaces. During cold starts, the engine operates under heavy load, preventing the oil from providing adequate lubrication due to its high viscosity at low temperatures, leading to metal fusion and seizure. 2. For vehicles that have undergone major repairs, incorrect installation of main or connecting rod bearings may result in improper clearance adjustment, causing bearing seizure. More details about bearing seizure are as follows: Bearing seizure is one of the most severe engine failures. This phenomenon occurs when severe wear happens between the crankshaft and main or connecting rod bearings due to the absence of an oil film, causing the contact surfaces to reach extreme high temperatures. As a result, the crankshaft journal and bearings sinter and lock together, preventing the engine from rotating.
I've experienced bearing seizure once, and it really freaked me out. The main reason was insufficient oil supply - either the oil level was too low and not topped up in time, or the oil pump failed causing low oil pressure. The bearing shells then ran dry, generated heat, and burned out. Another cause is incorrect bearing clearance - improper adjustment during assembly or wear/deformation over time, where either too large or too small gaps lead to overheating and seizure. Engine overheating due to poor cooling system performance (like clogged cooling system or broken fan) also thins out the oil, reducing its protective ability. Contaminants in the oil (from neglected air filter changes, for example) are another culprit. When this happens, the engine can lock up and become irreparable, with astronomical repair costs. Regular oil level checks, timely oil/filter changes, and avoiding aggressive high-speed driving can prevent major disasters.
