Are you due for an oil change and wondering whether you should pick multigrade oil for your car?
Multigrade oils are usually the go-to option for modern vehicles because they adapt well to temperature changes and improve engine efficiency. But depending on your car and climate, monograde oil might also work.
For your better understanding, we’ll explain what multigrade oil is, its benefits, and how it compares to monograde oil. We’ll also help you choose the right oil based on your vehicle and driving conditions.
Let’s begin!
This Article Contains:
- What Is Multigrade Oil?
- What Are the Different Types of Multigrade Oils?
- What Are the Benefits of Using Multigrade Oil?
- Are There Any Disadvantages of Using Multigrade Engine Oil?
- What Is the Difference Between Monograde and Multigrade Oil?
- Should You Use Multigrade or Single-Grade Oil?
- 4 FAQs About Multigrade Motor Oil
What Is Multigrade Oil?
Multigrade oil is an engine oil that performs well at different temperatures — both high and low. It’s created by blending a base oil (synthetic oil or mineral oil) with an additive called the Viscosity Index Improver (VII).
The VII is a complex agent that helps motor oils maintain viscosity (their thickness or resistance to flow) when the temperature changes. When the oil is cold, the VII molecules stay tightly curled, allowing the oil to flow easily. As the oil heats up, these molecules stretch out, making the oil thicker so it doesn’t become too thin. This helps maintain proper lubrication and engine protection across different temperatures and under extreme pressure.
But how can you know if your motor oil is multigrade or monograde?
You can check the SAE viscosity grade on the oil container. Multigrade oils have two numbers separated by a “W” (like SAE 10W-30), while monograde oils have only one number (like SAE 5W). The Society of Automotive Engineers (SAE) developed the SAE J300 standard, which outlines how oil viscosity is measured and labeled.
For example, let’s take 10W-30 multigrade oil. Here:
- W stands for winter, and the number before it denotes the viscosity or oil flow at 0° F. The lower this number, the better the oil will perform in winter.
- The digit after W stands for a specific viscosity grade at a higher temperature (212° F). The higher the number, the more resistant the automotive oil is to thinning at the normal operating temperature.
Now that you know what multigrade oil is, let’s explore its types.
What Are the Different Types of Multigrade Oils?
There are three types of multigrade oil:
- Mineral multigrade: This is made from lightweight mineral oil mixed with a VII complex agent to adapt to temperature changes. This variety of multigrade oil is widely compatible with most standard engines, making it a reliable choice for routine oil changes.
- Semi-synthetic multigrade: This mix of mineral and synthetic base oils offers a high viscosity index and prevents thinning at a high temperature. It also provides better thermal stability and produces fewer acidic byproducts, preventing engine wear.
- Fully synthetic multigrade: This multigrade oil is highly refined at a molecular level, making it ideal for modern gasoline or diesel engine cars. Its high viscosity index resists breakdown (even under extreme pressure), reducing sludge deposits and protecting engine components.
But are these multigrade oils really beneficial for your car?
Read on to find out.
What Are the Benefits of Using Multigrade Engine Oil?
Multigrade oil prolongs engine life and boosts performance. Apart from these, here’s what it does:
- Performs reliably across seasons and a wide temperature range
- Ensures smooth cold starts and reduces the load on the battery by flowing easily at cold temperatures
- Maintains optimal viscosity and protects your engine at high temperature
- Extends oil change intervals by resisting oxidation, build-up of deposits, and thermal breakdown
- Minimizes fuel consumption by requiring lesser idle time and by providing high-speed temporary shear thinning
- Prevents corrosion of parts by offering adequate lubrication
- Protects the environment by lowering emissions and providing improved fuel efficiency
However, like any other engineered product, multigrade oil has a few limitations.
Keep reading to know more.
Are There Any Disadvantages of Using Multigrade Oil?
Multigrade motor oil comes with a couple of downsides:
- It can be expensive if you’re on a tight budget or drive an old vehicle with higher oil consumption.
- The special additives (VIIs) that help the oil adapt to temperature changes can start to break down over time. When that happens, the oil may become too thin to protect your engine properly, especially under high heat or heavy use.
You’ve seen the pros and cons of multigrades — but how do they compare to monograde oils?
Let’s find out.
What Is the Difference Between Monograde and Multigrade Oil?
Oils classified under the SAE J300 system that meet only one viscosity standard are called monograde or single-grade oil.
They differ from multigrade oils in the following ways:
1. Temperature Dependence
Monograde oil works well in hot or cold conditions but not both, meaning you might need a different oil in winter and summer. For example, 5W, 10W, 15W, and 20W are winter-grade oils ideal for colder temperatures. Meanwhile, SAE 20, 30, 40, and 50 are summer-time oils with a viscosity grade suitable for warmer temperatures.
In contrast, multigrade oils eliminate the need to switch. Their chemical composition allows multigrade oils to work across a wide range of temperatures — staying fluid in cold weather and thick in hot summers. For example, 10W-30 is a multigrade oil, where “10W” indicates cold-weather performance and “30” covers high-temperature protection.
2. Viscosity
Monograde oils have a fixed viscosity and can’t adjust as the engine heats up. This limits their protective ability across temperature fluctuations.
Multigrade oils, on the other hand, use additives that help maintain their viscosity and flow under varying engine temperatures. This way, regardless of how cold or hot your engine is, the oil will continue lubricating and protecting the moving engine parts from corrosion.
3. Application
With their stable viscosity, monograde oils suit old cars better as the engines in these vehicles have wider internal tolerances (the space between engine parts). They are also used in racing cars, where engines are fine-tuned to operate in known temperature ranges or under controlled conditions.
Multigrade oils are ideal for modern vehicles, as their engines are built with tighter tolerances. These engines require oil that flows easily at startup and maintains proper thickness at a high operating temperature.
With frequent warm-up and cool-down cycles in city driving, multigrade oils adjust quickly, ensuring adequate lubrication and shielding the engine from corrosion.
Now, let’s explore and decide which oil suits your needs better.
Should You Use Multigrade or Single-Grade Oil?
Your car owner’s manual is the best starting point when choosing your engine oil type — it specifies exactly what type your vehicle needs. Here are a few more key factors to keep in mind:
1. Climate
In colder regions, your engine needs oil that stays fluid enough to circulate quickly at low temperatures. Multigrade oil with a lower “W” rating is useful in this situation as it flows easily in the cold.
Likewise, in hot climates, heat can cause oil to thin out too much, making it less effective at protecting engine parts. Multigrade oil adjusts to these conditions, maintaining the right thickness even in high temperatures.
On the other hand, a single-grade oil can work if you live in a region with a stable climate, where temperatures don’t vary much throughout the year.
2. Car Type
Owners of classic or vintage vehicles often prefer single-grade oil. These vehicles were designed to have wider engine tolerances, so they may not require the advanced properties of multigrade oils.
Multigrade oil is ideal for modern vehicles, as it flows quickly through tighter engine spaces and reduces oil consumption. It ensures reliable performance across a wide range of temperatures, with improved fuel efficiency and longer engine life.
TIP: When choosing an engine oil type, review the product details on the container. Most labels will indicate whether the oil suits modern engines or specific driving conditions in the product description.
Still have doubts about multigrade oils?
Then, let’s look at additional information about the oils to help you make a better decision.
4 FAQs About Multigrade Motor Oil
Here are the answers to some common questions on multigrade oils:
1. What Is the Most Commonly Used Multigrade Engine Oil?
SAE 5W-30 is the most widely used motor oil among car owners in the United States. This automotive oil can stay fluid at temperatures as low as -22º F and as high as 95º F. It’s an ideal choice for gasoline or diesel engine vehicle owners living in regions with seasonal temperature changes.
2. Is Multigrade Oil More Expensive than Monograde Oil?
Yes, multigrade oil generally costs more than monograde oil. It contains special additives that enable performance across a wide temperature range, contributing to higher production costs.
Moreover, multigrade oils often use higher-quality base oils that boost durability and fuel economy. The combination of premium ingredients and advanced refining processes contributes to the higher price tag.
Even in multigrade oils, fully synthetic variants are typically the most expensive. They’re made from advanced synthetic base stocks and undergo extensive processing to deliver top-tier performance. In comparison, mineral-based multigrade oils are more affordable, though still pricier than standard monograde oils.
3. Is it Okay to Mix Multigrade and Monograde Oil?
No, mixing multigrade and monograde oils isn’t a good idea. These oils have different formulations and properties, so combining them can alter their viscosity and performance.
Driving with mixed lubricants in the car can diminish engine protection and, in some cases, even cause severe damage.
4. How to Choose the Right Engine Oil for Your Vehicle?
Keep these key tips in mind when choosing engine oil:
- Before purchasing the oil container, review the product details, packaging type, and additional information, such as the expiration date in the product brochure.
- Cross-check the product description with your owner’s manual to ensure the oil suits your vehicle.
- Pick the right SAE viscosity depending on your local climate and driving habits.
- Ensure that the oil meets current American Petroleum Institute or API standards. Based in Washington, D.C., United States, the institute sets standards (like API SM and API SN) to help engine oils meet modern performance requirements. For example:
- Oils rated API SA to SH are made for older engines — typically pre-1995.
- Those rated API SM, API SN, API SP, and so on are meant for modern engines. The higher the second letter, the more recent and advanced the oil formulation.
Get a Quick and Reliable Multigrade Oil Change with AutoNation Mobile Service
Multigrade oils are ideal for modern engines — they improve fuel economy, guard against wear, and offer stability in all seasons.
But if you are still unsure what’s right for your car, let a trusted auto expert guide you.
Better yet, AutoNation Mobile Service brings the mechanic to you. Our expert technicians are available seven days a week to help you choose the correct oil type and perform oil changes right from your driveway.
What’s more?
We offer upfront pricing and back our work with a 12-month, 12,000-mile warranty.
Contact us today for safe oil changes and car repairs.