What Happens If Your Car Runs Out of Oil While Driving?

Engine oil is one of the most important fluids in your vehicle. It keeps the engine lubricated and even helps a bit with cooling.

What Does Engine Oil Do?

Combustion engines are made up of hundreds of metal parts. Many of these parts belong to the rotating assembly, which consists of pistons, connecting rods, and the crankshaft. The rotating assembly spins very rapidly when you step on the gas, moving the cylinders up and down inside each piston.

Engine oil provides a thin protection layer between each metal part of the engine. As your engine spins, the pistons and crankshaft slide on this thin film of oil, preventing metal on metal contact.

Without engine oil, your engine would likely only run for mere minutes. An engine with no oil wears out very quickly. You could experience rod knock, overheating, or even broken engine components.

Signs Your Oil Level Is Low

If you notice any of these signs, pull over as soon as it is safe to do so and check your engine oil level.

1) Oil Pressure Warning Light

The quickest way to know you’re out of oil is when you see the oil pressure warning light. This light is usually red and looks like an old fashioned oil can, but may be amber or orange in color.

Sometimes this light comes on when you have a bad sensor, such as the oil pressure sensor. You can tell if you actually have low oil pressure by doing an oil pressure test while the vehicle is running. If the oil light stays on while you have good oil pressure, it may just be a bad sensor.

2) Rod Knock

Rod knock is one type of damage that results from running with low or no oil for too long. Rod knock is a sound that results from excessive crankshaft journal or bearing wear.

Excessive wear in the crankshaft bearings allows the connecting rod to have excessive play as the crankshaft rotates, causing a knocking sound that comes from the bottom end of the engine as the rotating assembly spins.

3) No Oil on the Dipstick

If you check your oil and see nothing on the dipstick, chances are you need to add a fair amount of oil. Make sure you are parked on a level surface. Start with a quart of oil, and top up until you start to see oil on the dipstick. Bring the oil level up to the full line.

How Do I Know I’m Low On Oil?

The best way to know when you’re low on oil is to check the oil level regularly. The oil pressure warning light is there as a last resort to save the engine. When you see that light, there is a possibility that you’ve already experienced excessive wear inside your engine.

How to Know if Damage Has Been Done

Here are some relatively easy ways you can tell if you’ve done any damage to your engine from oil starvation.

1) Listen to Your Engine

Do you hear any strange metal on metal noises while your engine is running? Excessive engine damage is usually pretty easy to hear, because you will notice some very bad sounds coming from inside your engine.

Rod knock and similar engine damage usually present themselves as a loud clacking noise that speeds up with engine RPM. The noise is so abrasive, most people will hear the sound and know there is a problem.

Rod knock is not the same as pinging (also called “engine knock” or pre-ignition), which is the sound of gasoline detonating before it is ignited by the spark plug. Pre-ignition sounds like marbles in a can, and is typically a result of bad timing, spark, or fuel rather than a problem with the engine oil itself.

2) Perform a Compression Test

An engine makes power by compressing the air-fuel mixture in each cylinder and then igniting it at a very specific time. The more compression your engine has, the more power it can make.

A compression test is an easy way to check the general health of your engine. Compression tests hook up a gauge to each spark plug hole (after removing the spark plug). The engine is then cranked for several seconds and a pressure reading is given (in PSI or kPa).

When performing a compression test, it is important to check that each cylinder gives a relatively similar number to all other cylinders. If one or more cylinders have lower compression than the rest, this may indicate that you have a problem.

If you have a less than stellar compression test result, you may want to consider performing a leak down test to see where you are losing compression.

A leak down test pumps compressed air into each spark plug hole. You can measure the compression loss in each cylinder, and listen for where that air is escaping to determine where you have a leak in that cylinder’s seal.

3) Look for Metal Shavings in the Oil

When you go to change your oil, look for metal shavings in the used motor oil. Metal shavings or glitter in the oil is a sign that your engine is experiencing excessive wear.

If you notice this type of wear but your engine otherwise runs fine, the best thing you can do is to change the engine oil and increase your oil change interval in the future.

Verify that you are running the correct viscosity oil according to the manufacturer’s recommendations. It’s also a good idea to check that your oil meets any additional manufacturer specifications, such as the API oil category.

4) Used Oil Analysis

A used oil analysis may pick up on contaminants and metal in your oil that is too small to see. Several companies offer used oil analyses. One such company is Blackstone Labs.

When you do an oil analysis, the oil analysis company will send you a bottle. You will use this bottle to collect an oil sample when it comes out of your vehicle.

Once you’ve collected your sample, send it back to the oil analysis company. After paying a small fee for the service, you will receive a detailed description of each element that was found in your oil.

Used oil analyses work best when you send in a sample after each oil change. This allows you and the oil analysis company to track your engine health over time. The oil analysis company may even be able to give you a custom oil change interval based on your specific vehicle and use case.

5) Loss of Power

Although there are many causes of a loss of power, oil starvation is one of them. If you start to notice your vehicle isn’t running as well as it used to, check to make sure you’re not running it low on oil.

How To Check Your Oil

Park the vehicle on a level surface with the engine off. Pop the hood, and locate the engine oil dipstick. The top of the dipstick is usually yellow. Pull out the dipstick, wipe it off, and push it all the way into the dipstick tube. Remove the dipstick once more and note the oil level.

If you do not see oil on the dipstick after doing this, you are low on engine oil. If the oil level is between the low and full lines, your engine oil level is OK. You may want to top up the oil to reach the full mark, just to make sure you have enough oil until the next time you check it.

How Often Should I Check My Oil?

It’s a good idea to check your engine oil about as often as you fill up your gas tank. Some vehicles burn oil over time, and it’s not uncommon for manufacturers to find it acceptable for their engines to burn an entire quart every 1,000 miles.

Some vehicles that use synthetic oils call for 6,000 or even 10,000 mile oil change intervals. If you burn a quart every 1,000 miles and go 10,000 miles without changing your oil, your engine will definitely be starved of oil if you don’t top off before your next service.