What To Do When The Oil Light Is On: Quick Guide

When your oil light is on, pull over immediately and shut off your engine

There are two kinds of oil lights: an oil pressure light and an oil level light. Most vehicles only have an oil pressure warning light.  Usually, only luxury cars have both. Unless you know for sure that your car has an oil level light, you should assume yours is an oil pressure light. When the oil light comes on, it means your engine oil pressure has dropped to less than 7-psi. and continuing to drive can destroy your engine. So pull over immediately and shut off the engine.

What to do when your oil light comes on

• Pullover immediately and shut off the engine.
• Check the oil level on the dipstick

If it’s below the minimum markings, call roadside assistance or a friend to bring you more oil. Adding the wrong oil is better than running your engine with low or no oil. Do NOT continue to drive. You can destroy your engine, costing you thousands! If you can’t get someone to bring you oil, CALL A TOW TRUCK. A tow will be much cheaper than the cost to replace your engine.

Ok, your engine has low oil pressure, but what’s the cause?

• Your engine is extremely low on oil, so much so that the pump can’t suck up enough oil to maintain proper oil pressure.
• Your oil pump is worn out and can’t produce enough pressure
• The oi pressure relief valve is stuck open and is dumping all the oil pressure back into the oil pan
• The oil pressure sensor or the wiring to the sensor is faulty and you’re getting a false low oil pressure warning

How to determine if you have a bad oil pressure sensor

Rent an oil pressure gauge and an oil pressure socket from an auto parts store. Disconnect the electrical connector to the oil pressure sensor and unscrew the sensor. Screw in the fitting for the oil pressure gauge. Then start the engine and read the gauge to see if it’s at least 7-psi and rises as you increase engine speed. If it does, replace the sensor. If it doesn’t you’ve got more serious problems like a bad oil pump, stuck oil pressure relief valve or worn crankshaft bearings.

Worn bearings usually only cause the oil light to come on at idle

Worn crankshaft or camshaft bearings can cause low oil pressure. That causes the light to come on at idle when  your RPMs are low. But the light often goes off as you increase RPMs. A shop can test bearing wear by removing the oil pan and using Plastigauge to measure bearing clearances and bearing condition

Worn crankshaft bearings cause low oil pressure. The severely worn bearings and scored crankshaft journal in this picture are caused by lack of normal maintenance. This engine must be rebuilt or replaced

©, 2021 Rick Muscoplat