Blog Car Care Advice Everything You Need to Know About Dirty Engine Oil
Car Care Advice

Everything You Need to Know About Dirty Engine Oil

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Have you ever wondered if dirty oil truly poses a threat to your vehicle’s engine?
The answer, in short, is a resounding yes

Dirty oil isn’t just a minor inconvenience — it can wreak havoc on your engine and result in wallet-denting damages. 

So buckle up as we identify the signs of dirty engine oil, its root causes, and the potential consequences to help you maintain the longevity of your vehicle.

Let’s begin!

This Article Contains:

6 Tell-Tale Signs of Car Running on Dirty Engine Oil 

Here’s how you can confirm that your car is distressed and running on dirty motor oil: 

1. Dark and Thick Oil 

The easiest way to check if your car needs an oil change service is through a quick dipstick test. While doing the oil analysis, check the color and the oil viscosity (oil thickness). If the oil appears brown, grey, red (from a transmission fluid leak), or foamy (due to a coolant leak) — it’s contaminated. 

Likewise, thick, grainy, or gritty oil means it’s time for an oil change service. 

2. Unusual Sounds from the Engine

If you hear strange engine knocks or ticking sounds during ignition, it could indicate an overdue oil change.

When the oil gets old and degrades, it’s unable to circulate freely and lubricate the engine parts. This results in metal-on-metal contact between different engine components, creating knocking, ticking, or grinding sounds. 

3. Burning or Oil Smell

A strong burning smell from your car is often due to your engine overheating. Low or dirty engine oil prevents your engine from cooling down, resulting in overheating and a burning oil smell from the car. 

Note: An oil leak could also lead to a burning smell.

Either way, you should get your car checked by a mechanic ASAP

4. Smoke from Exhaust

Your car’s engine is engineered to minimize vehicle emissions. However, if you see excessive exhaust fumes, it could indicate that your car’s oil is preventing proper fuel combustion. Adding fresh oil should resolve this problem. 

5. Engine Vibrations

Has your everyday commute turned into a bumpy ride? 
Chances are that your engine may have a low oil level or degraded oil. The vibrations can result from excessive friction between the moving engine parts.

However, several other factors could contribute to this, including engine misfires due to insufficient fuel, dirty spark plugs, damaged engine mounts, etc. It’s best to have an experienced mechanic diagnose the root cause. 

6. Active Oil Change Light

Modern cars come with an array of sensors and dashboard lights to warn you about any car trouble. If your car has a low oil level or is running on heavily degraded oil, your engine’s computer will trigger the oil warning light (if equipped with one) or the check engine light

So, what causes your oil to get dark and dirty?
Keep reading!

What Leads to Dirty Engine Oil?

Here are the prime reasons that can degrade your engine oil: 

  1. Regular use: New or clean oil is translucent and amber-colored. However, exposure to multiple heat cycles can turn it dark. Also, as it circulates within the engine’s moving parts, the oil picks up impurities like ash metal particles, soot, moisture, etc., turning darker and thicker.
  1. Incomplete combustion: If your car engine isn’t running efficiently, incomplete combustion may occur. This leads to the production of unburned fuel and other byproducts that can contaminate the oil.
  1. Oil additives breakdown: Engine oil additives enhance its performance and protect the engine. Over time, these additives can break down, reducing their effectiveness and potentially contributing to a change in oil viscosity.
  1. Delays in oil change: If you don’t get an oil change at the recommended interval, it can lead to dirty oil circulating in your vehicle, causing engine damage. 
  1. Old and clogged oil filter: Just as you change old oil, you need to replace your old oil filter too. Failing to do so could lead to sludge buildup on the filter. It won’t be able to filter out the impurities in your engine oil. 

You may ignore an overdue oil change, putting it off to a more convenient time. But it isn’t a smart move. 
Let’s find out why. 

How Long Can You Drive with Dirty Engine Oil?

If your car keeps running on poor-quality oil, it won’t be long before your engine calls it quits.
Here’s what happens when you drive with dirty motor oil: 

Fret not! You can prevent such catastrophic damage and engine wear by getting regular oil changes. 

That brings us to the following question: 

How Frequently Do You Need an Oil Change?

Typically, vehicles need clean oil every six months or between 6,000-7,500 miles. Newer engines that use synthetic blends or fully synthetic oils can even go 7,500-15,000 miles without an oil change. 

But if you drive an older car, it may require new oil more frequently — every 3,000 miles.

You should always follow the recommended oil change interval given in your owner’s manual. That said, also consider your driving habits, traffic conditions, vehicle load, etc., to determine how often you need an oil change service. 

If unsure about your oil change interval, it’s best to consult a certified technician to assess your vehicle’s health and determine how frequently you’ll need to replace old oil. 

Moving on, let’s address any additional doubts you may have about engine oils.

3 FAQs on Engine Oils

Here are answers to some burning questions on motor oil: 

1. Why is Engine Oil Important? 

Engine oil is like the lifeline of your car, performing several critical functions for your engine.

2. How Much Does an Oil Change Cost?

Generally, a new inventory of engine oil and oil filter can cost between $35-$75 for conventional oil. Most engines take about 5-8 quarts of oil. Remember, conventional oil degrades faster. 

Going for synthetic oil will cost slightly more — $65-$125. However, synthetic oil lasts longer, so you’ll need less frequent oil changes. 

3. Does Dirty Engine Oil Cause Overheating?

Yes, your vehicle’s oil, if degraded, can cause your engine to overheat due to decreased lubrication and lack of head displacement. If ignored, it can result in severe engine damage and may even cause your motor to seize completely. 

It’s essential to get regular oil changes and use the correct type of new oil to slow down engine wear and maintain its peak performance. 

Keep Your Engine Well-Oiled With AutoNation Mobile Service

The health of your vehicle’s engine is intricately tied to the quality of its lifeblood — engine oil. 

So, if your car is giving you distress signals like excessive exhaust fumes, and you know that an oil change is overdue, don’t wait. Have an expert mechanic from AutoNation Mobile Service come to you and change your motor oil in your driveway. 

We’re a mobile auto repair and maintenance solution, available 7 days a week. We also offer a 12-month | 12,000-mile warranty on all repairs. 

Contact us to get your car purring smoothly.