An engine needs oil to lubricate moving parts, prevent corrosion, collect dirt and sludge, and absorb some of the heat generated by a running engine. The oil pump provides the force that delivers oil through galleries and passages around the engine. Oil pumps are usually either inside the oil pan and driven by a camshaft or outside the pan and driven by a crankshaft. When those engine parts start moving, the pump starts working at the same time to pump oil to reduce friction and wear between moving parts and prevent the engine from seizing. If an oil pump stops working, or there is little or no oil because of leaks, engine parts can overheat in a matter of seconds and seize from a lack of lubrication. Checking or replacing an oil pump is not part of routine service or maintenance, but because it’s critical to an engine any warning signs should be addressed immediately. An illuminated oil system warning light (usually red with the outline of a vintage oil can) or low-pressure indication on an oil pressure gauge are signs that the oil level is extremely low, the pump is not operating at normal speed or there’s a related problem that needs prompt attention. When a warning light comes on, the best approach is to shut the engine off, wait several minutes and check the oil level. If the oil level is normal and the warning light comes on again when the engine is restarted, continuing to run the engine increases the risk of major damage.