What it Does
The oil pressure warning lamp illuminates if engine oil pressure drops dangerously low.
Why This Matters
Oil pressure is required for healthy engine bearing lubrication. Merely flowing the oil is not enough. Oil pressure must maintain a film of oil between metal components that could otherwise wear against each other. For example, oil pressure can be used to suspend a spinning camshaft or crankshaft within the circular bearings so that metal pieces are kept from touching and the shaft is supported by hydraulic pressure! This concept is part of the reason why engines can last so for so long.
Possible Problems and Concerns
Low engine oil pressure
This is a major concern for engine health and longevity. Lack of oil pressure can both cause internal engine problems or be caused by internal engine problems.
Warning System Failure
There are cases in which these lamps illuminate at the wrong time. For example, a faulty pressure switch may trip the warning light when oil pressure is actually ok.
Mis-Understanding
The oil pressure lamp is not used for monitoring the oil level or indicating that it’s time for an oil change. It is only used to warn of low oil pressure. Relying on this indicator as a level monitor or oil change timer can result in running the engine drastically low on oil or far too long in-between oil changes, and engine health and longevity can be severely compromised as as a result.
Missed Warning
If the oil pressure warning illuminates, the vehicle engine should be turned off as soon as possible. It should be turned off immediately if possible. Running the engine without oil pressure can result in severe internal engine damage and this damage can happen quickly.