What is a common result of worn main or rod bearings in an engine?

Worn main or rod bearings typically lead to lower than specified oil pressure in an engine. This reduction in oil pressure occurs because the bearing surfaces, which should fit tightly together, begin to wear out and develop increased clearances. As the clearances increase, the oil can flow through the bearings too easily without creating sufficient pressure. The oil pump, which relies on the resistance created by properly fitted bearings to build pressure, will struggle to maintain the necessary oil pressure levels when those bearings are worn.

Inadequate oil pressure can lead to insufficient lubrication, which can cause further damage to engine components over time. This is why monitoring oil pressure is crucial for the health of an engine; low pressure indicates that there may be underlying issues such as bearing wear.