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5W20 vs 5W30 Oil: The Key Differences + 3 FAQs

October 29, 2021

5W20 vs 5W30, which one should you use?

When choosing the right multi grade oil for your car, you need to consider your car’s normal operating temperature and mileage requirements, among other things.  

Generally, 5W-20 oil is the better choice in low temperatures and colder climates. 

But is that the right oil for your car? 

In this article, we’ll see how these multigrade oils compare. We’ll also look at a few related queries, including whether you can use 5W-30 instead of 5W-20 or if you can mix the two

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Let’s get started! 

5W20 Vs 5W30 Oil: What’s The Difference? 

5W-20 and 5W30 motor oil are winter viscosity grade oils primarily recommended for older engines and light-duty use. These oils are best utilized in colder temperatures. 

Both oils exhibit the properties of the SAE 5W winter oil type, but here’s how they’re different:

A. Operating Temperature

A multi grade oil is graded using the “XW-XX” format. 
Here, the ‘W’ stands for ‘Winter,’ the number before it denotes the oil’s viscosity under 0°C (32°F), while the numbers after it represent the viscosity at 100oC (212°F). 

As both these oils have a winter viscosity of ‘5W’, they’re a great winter viscosity grade oil (the lower the number is, the better the oil performs in cold temperature settings).

When it comes to their higher operating temperature performance, 5W30 motor oil performs slightly better than 5W-20 and is a thicker oil than its counterpart

5W30 motor oil would be more robust and not break down very easily at a higher temperature. Thus, it will protect your engine parts better under moderate oil pressure and high temperature settings. 

B. Gas Mileage

Generally, lower viscosity (thinner oil) provides better fuel efficiency for your car. 

How? 
At normal operating temperature, a lower viscosity oil will provide a thinner barrier of protection between your engine parts, thus reducing friction and improving the engine performance. This impacts your car’s fuel efficiency and gas mileage.

5W-20 oil, being the lower viscosity oil (thinner oil) than 5W-30, might help boost your fuel economy. And although you may not notice a vast difference, it does add up over time. 

However, remember that you should always use the motor oil recommended for your car by your engine manufacturer or mechanic

Even though 5W-20 motor oil is good for fuel economy, replacing your regular oil with it can mean more harm than good for your engine. 5W-20 engine oil is only ideal for low to moderate temperature use in colder climates.

So does that mean 5W-20 oil is better than 5W-30 oil? 
Let’s find out. 

5W20 Vs 5W30: Which Oil Is Better? 

Neither of the two oils is any better or worse than each other. 
It all depends on your engine requirements and car type. 

When choosing the right multigrade engine oil for your car, you should consider two factors:

Although some cars do allow some flexibility in engine oil options, most have a recommended viscosity grade. This is because the engines are tuned to run on a certain oil viscosity, and changing that could affect your engine’s performance.

Ideally, 5W 30 oil is perfect for people who drive in seasonal or hotter climates. It has a better viscosity index than 5W-20 oil and is more versatile in terms of its warmer temperature range. You’ll get better protection with 5W 30 oil in cold as well as hotter climates.

5W-20 oil is best for those who live in colder climates with low temperatures. It can be used for light-duty applications, for engines that do not reach very extreme temperatures. 5W-20 oil provides excellent start-up performance in colder temperatures.

Note: Older vehicles may need a high mileage variant of their regular oil (5W-20 or 5W-30). In this case, the high mileage oil better protects the engine at extreme temperatures from friction and engine drag.

Keeping this in mind, here’s what you need to know about 5W-20 vs 5W-30 oil. 

4 FAQs About 5W20 Vs 5W30 Oil

Let’s take a look at a few queries on 5W-20 vs 5W 30 oil and their answers:

1. What Happens If You Use 5W-30 Instead Of 5W-20 Oil?

You can use 5W-30 oil instead of 5W-20 oil if your engine allows for it. 
The safest way to make sure that it does is to consult your owner’s manual. 

If it doesn’t, you’re putting your engine at risk for engine damage and reduced performance. 

This is because exposing your engine to slightly thicker oil than it’s used to leads to more friction. Your engine has to work harder to perform its duties with the added resistance of the thicker oil.

The increased friction due to a heavier oil can slow down your internal combustion engine and cause problems like oil leaks, engine deposits, and sludge formation. 

On top of that, the wrong oil in newer engines may void them of their warranty, and put your engine at risk of eventual engine damage.  

2. Can You Mix 5W-20 And 5W-30 Oils?

While some engines may allow it, most mechanics will advise you against mixing two multigrade oils. In some cases, using the wrong oil or mixing two different oils can null your car’s warranty and cost you a fortune in repairs.

You’re also risking your engine life and weakening the internal combustion engine’s durability.

Mixing 5W-20 and 5W-30 (or any other oils for that matter) may lead to faster wear and tear of your engine and eventually cause problems with the basic functioning of critical engine parts.

And even if your engine allows it, you won’t get any noticeable results by mixing different viscosity grade oils. So even if your car engine is versatile in terms of the oil viscosity grade it uses, it’s best to stick to a single viscosity rating at a time.

3. Are 5W-20 And 5W-30 Oil Synthetic? 

Both 5W-20 and 5W-30 oils are available in conventional and synthetic oil variants. 

Conventional oil is made using refined crude oil as base oil, along with various additives (like a viscosity index improver or corrosion inhibitor). It provides decent fuel economy, protection against friction and damage to various engine parts. 

However, conventional oil doesn’t last as long as synthetic oil. 

Synthetic motor oil, on the other hand, is very reliable and highly stable in extreme temperatures. 

In fact, a 5W-20 synthetic oil may perform even better in a warmer temperature than 5W-30 conventional oil. This is because synthetic motor oil is made by breaking down and rebuilding hydrocarbon atoms for a more stable operating temperature range. 

5W-20 and 5W-30 oils are also available as synthetic blend variants. Synthetic blend multi grade oil will perform better than regular oil and be cheaper than the synthetic oil type. 

Note: Older or high mileage engines may require a special high mileage oil to properly protect the engine. High mileage vehicles are those that have more than 75,000 miles on them. 

If your car falls under this category, consult your car mechanic for the right kind of high mileage oil for your car (5W-20 or 5W-30). 

4. What Happens If You Use The Wrong Oil In Your Car?

If you accidentally used the wrong oil for your engine, the first thing to do is drain out your oil and get an oil change. While it may not cause any immediate damage to your engine life, it’s best not to risk it. 

If you’re on the road with no means to replace your oil, follow these instructions:

Keep in mind, you should always maintain a close eye on the type of oil you use for your engine. If your mechanic accidentally refills the wrong oil, let them know and get an oil change. 

Otherwise, you may run into problems like unusual engine noise, oil leaks, and engine deposits. You may also detect a burning smell from the engine, reduced fuel efficiency, and increased oil consumption. 

Closing Thoughts 

When choosing between 5W20 vs 5W30 oil, your vehicle manufacturer’s manual should be able to tell you everything you need to know. And if it doesn’t, reach out to your car mechanic for the best-suited viscosity grade for your car.

However, irrespective of which oil you choose, remember to conduct regular maintenance and oil change routines for healthy engine life. 

And if you need any help with your car’s maintenance and repair, oil-related or otherwise, reach out to RepairSmith!

RepairSmith is a mobile car maintenance and repair service, providing competitive and upfront pricing for a range of car-related solutions. Contact them to have ASE-certified mechanics at your doorstep!