Engine & Oil
Checking Your Engine Oil
The single most important check you can do
Engine oil is the quiet hero of your car. Learning to check it takes about five minutes and can save you thousands of dollars in engine damage.
Basics
What engine oil actually does
Oil coats the metal parts inside your engine so they glide instead of grinding. It also carries heat away and holds tiny bits of dirt so they do not wear the engine down. Without enough clean oil, metal rubs metal — and that damage happens fast, sometimes in minutes.
Warning signs
The red oil-pressure light is an emergency
If the red oil-pressure warning light comes on while you are driving, safely pull over and shut the engine off as soon as it is safe to do so. Driving with low oil pressure can destroy an engine in a very short distance. It is not a "get to it this week" light.
Low oil level vs. low oil pressure — they are different
Low oil level means there is not much oil left in the engine — the dipstick reads low. Low oil pressure means the remaining oil is not being pushed through the engine properly. A level problem can be topped up; a pressure problem means stop driving. You cannot fix oil pressure by pouring oil in.
Dipstick or electronic?
Older and many current cars have a metal dipstick you pull out and read. Some newer cars have no dipstick at all and show the oil level on a screen — often through a menu, and sometimes only once the engine is warm. Check your owner's manual so you know which one you have.
Step by step
How to check a dipstick, step by step
- 1
Park on level ground
On a slope the reading will be wrong.
- 2
Turn the engine off
Let it sit and cool for several minutes as your manual directs, so the oil settles back into the pan.
- 3
Pull the dipstick out
It usually has a bright loop or handle, often with an oil-can symbol.
- 4
Wipe it clean
Use a rag or paper towel so you can see the true level.
- 5
Reinsert it fully
Push it all the way back in.
- 6
Pull it out again and read
Look at where the film of oil stops on the stick.
What normal looks like
What the dipstick can look like
Normal
Between the marks
Low
Below the low mark
Overfilled
Above the high mark
Dirty / dark
Normal for used oil
Milky / foamy
Possible coolant mixing
The two dashed lines are the low and high marks. A safe level sits between them — dirty color alone does not mean the oil needs changing.
Reading the level
- The dipstick has a low mark and a high mark (sometimes holes or a hatched area).
- A safe level is anywhere between them, ideally nearer the top.
- Below the low mark: add oil soon.
- Above the high mark: too much oil — this can cause problems too, so do not overfill.
Step by step
Adding oil gradually
- 1
Use the right oil
Find the viscosity and specification in your manual or on the oil cap — for example "0W-20" or "5W-30".
- 2
Add a little at a time
Pour in about half a quart through a funnel into the oil-fill opening.
- 3
Wait, then re-check
Let it settle, then check the dipstick again.
- 4
Repeat until safely in range
It is much easier to add more than to remove extra oil.
Quick tip
Use the oil your maker specifies
The wrong thickness of oil can affect how well your engine is protected. Match the viscosity and specification in your owner's manual exactly when you buy oil.
Warning signs
Warning signs to take seriously
- The red oil-pressure light glowing or flashing.
- Fresh dark puddles under the car where you park.
- A burning or oily smell while driving.
- A heavy knocking or tapping sound from the engine.
- The level dropping quickly between checks.
Recommendations vary by vehicle
Intervals, fluids, and procedures differ a lot between cars. Use this lesson to understand the idea, then follow your manufacturer's owner manual for your exact vehicle.
