"The blood of your vehicle isn't gasoline, it's oil." This statement from veteran mechanic John Richardson perfectly captures the critical role engine oil plays in your car's health.

Like blood in our bodies, oil circulates through the engine, providing lubrication, cooling, and protection. But how do you know when something's wrong with this vital fluid? Let's dive into the signs that your car's engine oil might be low or overfilled, and what you can do about it.


The Importance of Proper Oil Levels

Engine oil serves multiple crucial functions in your vehicle. It reduces friction between moving parts, transfers heat away from combustion areas, and helps prevent corrosion. Too little or too much oil can severely damage your engine and lead to costly repairs.

According to a study by the Car Care Council, 22% of vehicles have low or dirty engine oil, yet many drivers remain unaware until serious problems develop. This oversight is completely preventable with regular checks and maintenance.


Signs Your Engine Oil is Low

Dashboard Warning Lights

The most obvious indicator is your oil pressure warning light. When it illuminates, stop driving as soon as safely possible! This red or amber light typically resembles an oil can or shows the word "OIL."

Modern vehicles may have sophisticated oil monitoring systems that calculate oil life based on driving conditions and alert you before critical problems arise. Don't ignore these warnings, they're your first line of defense.

Unusual Engine Noises

Low oil levels reduce lubrication between engine components. Listen for:

  • Knocking sounds (particularly when accelerating)
  • Increased overall engine noise
  • Ticking or tapping noises (especially prominent when starting your car)

These sounds occur because metal components are making direct contact without sufficient lubrication. I've seen engines completely destroyed from just a few minutes of running with critically low oil.

Burning Smell

Notice a hot, burning odor while driving? Oil may be leaking onto hot engine components. The smell is distinctive, somewhat similar to burning rubber but with a petroleum edge. Pull over safely and check for visible leaks under your vehicle.

Poor Engine Performance

Low oil levels can cause your engine to run roughly or lose power. You might notice:

  • Hesitation during acceleration
  • Unusual vibrations
  • Overall sluggish performance

These symptoms occur because increased friction makes it harder for engine components to move efficiently. Source


Signs Your Engine Oil is Overfilled

Overfilling is less common but equally problematic. Here's what to watch for:

Blue/White Exhaust Smoke

Excessive oil can enter combustion chambers and burn along with fuel. The result? Blue or white smoke billowing from your exhaust pipe. This isn't just an environmental concern, it indicates internal engine problems that could become serious.

Oil Leaks

When there's too much oil, pressure builds in the crankcase. This can force oil past seals and gaskets, creating leaks around the oil filter, pan gasket, or front and rear main seals. Look for dark puddles under your car after it's been parked.

Foaming Oil

Checking your dipstick may reveal frothy, foamy oil resembling a milkshake. The crankshaft whips excess oil into a foam, reducing its lubricating properties and potentially causing air bubbles that prevent proper oil circulation.

Erratic Engine Performance

Overfilled oil can cause the crankshaft to make contact with the oil, creating resistance. You might notice:

  1. Rough idle
  2. Reduced power
  3. Inconsistent acceleration
  4. Unusual engine sounds

In severe cases, this can lead to blown seals or even catastrophic engine failure. Source


How to Check Your Engine Oil Level Properly

Follow these steps for an accurate reading:

  1. Park on level ground with the engine off and cooled for at least 10 minutes (this allows oil to settle in the pan).
  2. Locate the dipstick – usually has a bright yellow or orange handle marked "Engine Oil."
  3. Remove, wipe, reinsert, and check – Pull the dipstick out completely, wipe it clean with a lint-free cloth, reinsert fully, then pull it out again to check.
  4. Read the level – Oil should be between the "MIN" and "MAX" or "L" and "F" marks. The ideal level is near the upper mark without exceeding it.
  5. Check oil condition – While you're at it, examine the oil's color and consistency. Clean oil appears amber and transparent. Dark, gritty, or milky oil indicates problems requiring attention.

Engine oil levels

Example of proper oil level readings on a dipstick. The oil level should be between the MIN and MAX marks.

What to Do When Oil Levels Are Off

If Oil is Low:

  1. Add oil gradually – Use the grade recommended in your owner's manual (typically something like 5W - 30 or 10W - 40).
  2. Add in small increments – Pour about a quarter quart at a time, then recheck. It's much easier to add more than to remove excess!
  3. Check for leaks – Consistent low oil levels suggest leakage. Look for oil spots under your parked car or dark streaks on engine components.
  4. Monitor consumption – If your car regularly needs oil between changes, track how much you're adding and how often. This data helps diagnose underlying issues.


If Oil is Overfilled:

  1. Drain excess oil – This is best done by a professional who can safely access the drain plug or use an extraction pump.
  2. Never try to "burn off" extra oil by driving aggressively – this can cause serious engine damage!
  3. If significantly overfilled, have your car towed to avoid potential damage from driving.


Prevention is Better Than Cure

Here's my professional advice after years in the field: check your oil level at least once a month and before any long trips. This five-minute task can save you thousands in repair costs!

A regular oil change schedule based on your manufacturer's recommendations is equally important. Most modern vehicles need oil changes every 5,000 to 10,000 miles, but this varies based on driving conditions and oil type.

Remember that extreme temperatures, towing heavy loads, or frequent short trips can accelerate oil breakdown and consumption. In these cases, more frequent checks are essential.


Final Thoughts

Your engine is a precision machine with components operating at high temperatures with tolerances measured in thousandths of an inch. Proper oil level isn't just a maintenance suggestion, it's a necessity for engine longevity.

I've rebuilt too many engines that failed prematurely due to improper oil levels. Don't let your vehicle become another statistic! With these guidelines, you can confidently monitor your car's engine oil level and help ensure years of reliable service.


What other maintenance concerns do you have about your vehicle? Share in the comments, and I'd be happy to address them in future articles!