Which factor should be checked first if the engine exhibits low oil pressure?

When diagnosing low oil pressure in an engine, the first factor to check is the oil level. Oil is essential for maintaining pressure within the engine, as it creates a hydraulic barrier that allows components to operate smoothly. If the oil level is low, it can result in insufficient lubrication, leading to increased friction, wear, and potential engine damage.

Low oil level can occur due to a leak, an oil consumption issue, or simply because the engine hasn't been serviced frequently enough. Therefore, confirming that the oil is at the correct level is a crucial step in troubleshooting low oil pressure. This will help determine if the pressure issue is related to insufficient oil or if further investigation into other potential causes, such as oil pump failure or clogged oil passages, is necessary.

The other factors listed—spark plugs, radiator condition, and belt tension—are not directly related to oil pressure and would not be the most relevant considerations when addressing low oil pressure conditions.