Your engine works hard every time you drive, and engine oil keeps it running smoothly. It’s not just a fluid but your car’s first line of defense against wear, heat, and sludge.
However, not all engine oils are the same. Pour in the wrong one and you could be trading horsepower for reduced performance, efficiency, and even shorter engine lifespan.
In this guide, we’ll break down what engine oil is, why it’s crucial for vehicle longevity, and how to ensure your car always has the protection it needs. We’ll also help you identify when your car needs an oil change.
This Article Contains:
- What Is Engine Oil?
- What Does Engine Oil Do?
- What Is Oil Viscosity?
- What Are the Common Types of Engine Oil
- How to Pick the Right Oil for Your Car
- Why Is It Important to Change Engine Oil at Timely Intervals?
- How Do You Know Your Car Needs an Oil Change?
What Is Engine Oil?
Engine oil (or motor oil) is a lubricant that helps reduce friction and wear on engine parts.
How?
It forms a thin film between metal parts (pistons, bearings, and more), reducing direct metal-to-metal contact.
So what is it made of?
Engine oil is a mix of base oil and certain additives that serve various purposes.
These additive compounds include:
- Dispersants: Keep sludge, soot, and contaminants suspended in the oil to prevent the formation of harmful deposits inside the engine.
- Detergents: Clean high-temperature engine parts by preventing deposit buildup and neutralizing acids.
- Antioxidants: Prevent the oil from breaking down too quickly, which helps stop thick sludge from forming inside the engine.
- Viscosity index improvers: Help maintain optimal oil thickness across a wide temperature range.
- Corrosion inhibitors: Protect metal parts from acidic corrosion and moisture-induced rust.
- Friction modifiers: Reduce friction between engine parts, helping the engine run more efficiently.
- Antifoam additives: Prevent foam formation in oil and ensure proper lubrication as well as cooling.
- Pour point depressants: Lower the oil’s pour point to improve its ability to flow during cold starts and protect the engine in low temperatures.
- Antiwear additives: Form a protective layer on metal surfaces to prevent wear under high oil pressure and temperature.
This carefully engineered composition helps your engine run smoothly and reliably.
Let’s take a closer look at how engine oil benefits your car.
What Does Engine Oil Do?
You already know modern engine oils are made with compounds that clean, protect, and lubricate.
But what does that actually mean when you’re behind the wheel?
Here’s how engine oils help in your everyday driving:
- Ensures smoother cold starts: On chilly mornings, a low-viscosity engine oil (covered next!) flows quickly to protect internal combustion engine parts when you turn the key.
- Prevents overheating in traffic: Whether you’re idling in a jam or cruising on the highway, oil helps carry heat away from engine components to keep things cool.
- Boosts fuel efficiency over time: Reduced friction inside the engine means your car doesn’t have to work as hard, meaning better mileage and fuel economy.
- Reduces engine noise and vibration: A well-lubricated engine runs quieter and smoother, especially under load or at high speeds.
- Extends engine life: Engine oil reduces wear and prevents harmful buildup, keeping your engine running stronger for longer.
- Supports modern engine features: Variable valve timing and turbochargers rely on clean, pressurized oil to function correctly — the right oil helps these systems work as intended.
Next, we’ll talk about oil viscosity and why it matters.
What Is Oil Viscosity?
Oil viscosity measures the oil’s thickness and resistance to flow — meaning how easily the oil moves through the engine, especially at different temperatures.
Based on this, we have:
- Low-viscosity oil (like 0W-20): Flows more easily, especially in cold temperatures, which helps with cold starts and quick lubrication.
- High-viscosity oil (like 20W-50): Flows more slowly, making it ideal for hotter climates or older engines. It also offers better protection at higher temperatures.
Wondering what 0W-20 or 20W-50 stands for?
The letter ‘W’ stands for ‘Winter,’ indicating that both oils suit cold weather conditions.
The numbers indicate the viscosity or thickness of the engine oil:
- The number before ‘W’ indicates the oil’s viscosity at a low temperature.
- The number after ‘W’ represents the oil’s viscosity at the engine’s operating temperature (or a higher temperature).
This means that the 0W-20 is a thin oil with a viscosity rating of 0 in low temperatures and 20 at the engine’s normal operating temperature.
Meanwhile, 20W-50 is a thicker oil with a viscosity rating of 20 at a cold temperature and 50 at the engine’s normal operating temperature.
But why is viscosity important?
Choosing the correct viscosity ensures proper lubrication, engine protection, and better performance under various driving conditions.
However, different engines need different oils.
So, what are your options?
What Are the Common Types of Engine Oil?
Motor oil is no longer just a mixture of base oil and additive compounds.
Here are the various types of motor oil that have evolved over time:
1. Conventional Motor Oil
Conventional oil or mineral oil is the standard motor oil manufactured from raw crude oil and then refined in a factory.
It tends to be less refined than its alternatives and doesn’t provide adequate protection against varying engine temperatures. The primary function of this oil is to lubricate engine components.
If your vehicle uses conventional oil, it’ll need more frequent oil changes due to its lower heat tolerance and oxidation resistance. However, it’s the cheapest of the lot.
2. Synthetic Engine Oil
Synthetic engine oil is entirely factory-made and highly refined. This synthetic lubricant remains stable across a wide range of engine temperatures, maintains a high viscosity, and protects your engine components against wear and tear.
Although synthetic lubricant is more expensive, it can last nearly twice as long as conventional oil. The oil also provides better engine performance and increased fuel economy.
3. Synthetic Blend Oil
Synthetic blend oil is manufactured using both crude oil and synthetic ingredients. It combines all the advantages of conventional motor oil and synthetic motor oil while minimizing their drawbacks.
Synthetic blend oil also contains viscosity modifier additives that help maintain oil viscosity under changing temperatures. It’s cheaper than synthetic oil and costlier than mineral oil.
4. High Mileage Oil
High mileage oil is carefully formulated with a unique blend of additive compounds that help reduce oil burnoff. It’s designed to prevent an oil leak in older, higher-mileage vehicles.
If your car has over 75,000 miles, you may want to switch to high-mileage oil.
Not sure which engine oil is right for your car?
We’ve got you covered!.
How to Pick the Right Oil for Your Car
You should select the engine oil with additives such as dispersants, antioxidants, viscosity index improvers, viscosity modifiers, friction modifiers, and detergents — all of which contribute to engine cleanliness, efficiency, and wear protection.
Your best bet is to consult your car’s engine manufacturer’s manual about your oil needs.
It’s also important to note that oil formulated for a gasoline engine may not be suitable for a diesel engine due to differences in combustion characteristics and required detergency levels.
Besides this, make sure your engine oil meets the latest performance standards, like:
- ILSAC (International Lubricant Standardization and Approval Committee) GF-6: This standard was developed to meet the needs of turbocharged gasoline direct injection (TGDI) engines. It offers enhanced engine protection, improves fuel efficiency, and supports longer engine life.
- API SP (American Petroleum Institute Service Category SP): This is the latest API engine oil standard, designed to provide superior protection against wear, combustion residue, and oxidation. API SP also addresses issues specific to modern engine technologies.
However, choosing the right engine oil is just the beginning; regular oil changes are just as essential to keep your engine healthy.
Why Is It Important to Change Engine Oil at Timely Intervals?
Every time your engine runs, combustion residue (soot, metal particles, carbon deposits, etc.) mixes with the engine oil, gradually contaminating it. Without regular oil changes, these impurities will form sludge inside the engine.
This sludge can restrict oil flow, reduce lubrication, and eventually cause serious engine damage.
So, when’s the ideal time to change it?
The average oil change interval for conventional oil is around 3,000-5,000 miles. However, modern engine oils like synthetic motor oil can last anywhere from 7,500 to 15,000 miles or 6 months to 12 months.
Your driving habits also affect how often you’ll need an oil change and oil filter replacement. If you drive in tough conditions, like extreme temperatures, rough roads, or heavy traffic, you may need more frequent services.
Next, let’s understand when you may need to change the oil earlier.
How Do You Know Your Car Needs an Oil Change?
Besides changing it at regular intervals, call your mechanic for an oil change when you notice:
1. Unusual Engine Noises
When your engine runs low on oil, friction between its parts can cause rumbling or knocking sounds. This indicates that the engine oil is too low or dirty and overdue for a change.
In contrast, a well-lubricated engine will never make a lot of noise.
2. Smell of Oil
If you get a strong odor of oil inside the vehicle, it could be oil leaking onto hot engine parts. It can also mean the oil is old and no longer protecting the engine, causing it to overheat.
The best step here is to have a mechanic check for an oil leak first, followed by an oil filter replacement and an oil change. This will prevent your car from burning oil unnecessarily in the future.
3. Exhaust Smoke
It’s normal for car engines to emit translucent, odorless vapor from the car’s tailpipe. However, pay close attention to your engine if this vapor turns into smoke.
Check the car’s oil level to see if it needs an oil change. It’s also a good idea to check the oil viscosity and make sure the oil is still good. If required, replace the oil to prevent any car engine problems.
4. Darker Oil
Standard multigrade oils are supposed to have a translucent appearance and a brown hue. If the oil looks very dark or blackish, it has been contaminated with sludge and needs to be changed.
5. Increased Engine Wear
If your engine feels rough, takes longer to accelerate, or makes strange noises, it could be a sign of increased wear — often caused by old motor oil insufficient oil level.
When oil breaks down or runs low, it can’t properly lubricate engine components, leading to friction and long-term damage. To avoid this, follow a consistent oil change routine depending on whether you use synthetic oil or traditional mineral oil.
6. Warning Lights
Some cars have a built-in alert system that notifies you when it’s time for an oil change. In some cases, you might also see the check engine light, especially if oil levels are critically low or oil pressure drops.
If you’re lucky, a simple oil change might be all it takes to turn that light off.
7. Excessive Vibrations
Old or degraded oil loses its ability to lubricate the engine properly. This leads to increased friction between moving parts, which can cause the engine to run rough.
The result?
You’ll notice shaking or vibrations, especially when the car is idling, accelerating, or under load.
Trust the Experts for Your Next Oil Change
Quality engine oil is a good investment for your car, as it provides some much-needed TLC to the internal combustion engine parts. That’s why following a regular oil change schedule is always important.
And when that time comes, you can rely on AutoNation Mobile Service.
We are a mobile auto repair and maintenance service available seven days a week. We provide upfront pricing, same-day services depending on your location, easy online bookings, and a 12-month, 12,000-mile warranty on all repairs.
Contact us to resolve your car problems right away!