How Long Can Synthetic Oil Sit in an Engine: Know Now!

Whether it is for traveling reasons or because we have one other better car, many of us often do not need to use our vehicle for a good period of time. Trust me, that is not good for the engine nor for the oil. Old oil will never ensure the best performance of your engine. 

And as synthetic oil is one of the best types of oil out there, most of us use it. But hey, how long can synthetic oil sit in an engine? 

Well, two years is the maximum amount of time synthetic oil can sit in an unused engine depending on a few factors. 

In this article, I’ll start by examining the factors that can impact the lifespan of synthetic oil. And try to give you a comprehensive understanding of how long synthetic oil can sit in an engine. Then I’ll show you how you can maximize its lifespan for optimal engine performance.

Factors Affecting Synthetic Oil Life in an Engine

There are several factors that will play a role in determining how long synthetic oil will last in your engine. Let’s dive into each of them:

1. Quality of the oil

Synthetic oil is known for its high-quality but you know, not all synthetic oils are created equal.

You will find differences using different brands and viscosity grades. Try to use the perfect viscosity grade according to the temperature and the best oil possible.

The quality of the oil can affect its longevity in the engine. So make sure to choose a reputable brand and a product that meets industry standards.

2. Storage conditions

The second factor is the storage conditions. 

Synthetic oil should be stored in a cool, dry place, away from direct sunlight. Are you doing that? Otherwise, it will surely affect the oil lifespan.

Wondering how? You see, exposure to heat and moisture can cause the oil to deteriorate faster.

 If you plan on storing the oil for an extended period, make sure the container is airtight to prevent contamination.

3. Engine usage

The amount and type of driving you do can also impact the longevity of synthetic oil in your engine.

For example, driving in hot, dusty conditions or making frequent short trips can cause your car’s oil to break down faster.

On the other hand, if you mostly drive on highways and have longer trips, your oil may last longer.

So you better keep an eye on the engine usage. 

4. Climate and temperature

You kind of have an idea about this one if you’re driving for a long time.

The climate and temperature you drive in can also have an impact on the life of synthetic oil in your engine.

Extreme hot or cold temperatures (For example, in the hot summer of Florida) can cause the oil to deteriorate faster, so it’s important to check on your oil’s performance in these conditions.

5. Age of the oil

Like most things, synthetic oil will naturally deteriorate over time, even if it’s not being used. 

If you have unused oil that’s been sitting in your garage for a while, it’s just better that you forget the calculations of time and dispose of it then start fresh.

That’s it! By being aware of these factors and taking steps to mitigate their impact, you can help ensure that your synthetic oil provides maximum protection for your engine.

How Long Can Synthetic Oil Sit in an Engine – A Detailed Explanation 

Let’s get to the main part. You already know it depends a lot on the above factors. But exactly how long?

Well, to give you an idea, it will be no more than 2 years.

It can vary by a couple of months more or less, depending on your own driving conditions. For example, if you make frequent short trips or drive in extremely hot or cold conditions, your oil may break down faster and need to be changed more often.

When synthetic oil sits idle inside the engine, it degrades and loses efficiency.

So, that will be a good outcome for the engine. Again, most experts agree that you should change your synthetic oil if it has sat in the engine for more than 24 months.

Let’s drive into more details.

Synthetic oils are known to be more durable and long-lasting compared to conventional oils. You will be glad to know that synthetic oils last from at least 7,500 miles to 10,000 miles on average.

What about conventional oils? Well, they last around 5000 miles. So, if you’re lucky, you might be getting double mileage in the case of synthetic oils.

However, we are talking about idle oil here, right? It is never a good idea to use an idle oil engine, regardless of the type of oil used.

My personal suggestion would be to just change your oil if it has been sitting in the engine for more than 6 months. What will happen when it’s more than that?

Oil will undoubtedly weaken further.It will lose its efficiency at lubricating, cleaning, and protecting the engine.

Eventually, all oils will break down and need to be changed, regardless of whether they are synthetic or conventional.

Regular oil changes are essential for maintaining the health of your engine.

It ensures that things run smoothly and efficiently for many miles to come.

That’s why it is always best to change your unused synthetic oil that has been sitting in an engine for more than six months.

One more thing! We are talking about average numbers.

It’s always best to consult your vehicle’s owner’s manual as well as the manufacturer’s recommendations for the specific brand and type of oil you’re using.

What Happens to Unused Synthetic Oil After Sitting in an Engine? 

Motor oil, including synthetic oil, is designed to provide essential lubrication and protection for your engine. 

However, if oil is left sitting inside an engine for an extended period of time, it can deteriorate and lose its ability to effectively lubricate the engine. In one word, it will go BAD. 

According to the experts, unopened synthetic oil can last around 7 to 8 years in its original container. But if you open it up, put it in the engine and leave it, it will surely definitely go bad.

Over time, the oil can become thick and viscous, reducing its ability to flow freely and effectively lubricate the engine.

What will happen then? It can increase friction and wear on engine components, leading to decreased performance and potentially damaging the engine.

And there’s more! This type of unused oil can be contaminated with debris as well. Different types of deposits and sludge might get created that will undoubtedly harm your entire engine.

That is why it is always best not to use these unused synthetic oils.

5 signs of Deterioration in Synthetic Oil

Whether you used or have unused synthetic oil in your engine if you see these signs consider changing the oil immediately. 

1. Dark Color

Synthetic oil starts off with a golden color, a kind of caramel color. But as it ages and accumulates contaminants, it can become darker.

So if your oil has taken on a dark, blackish appearance, it may be time for a change.

2. Unusual Odor 

Who doesn’t like the smell of petrol or oil? But hey, we like them brand new, not old and dirty. 

Synthetic oil should have a neutral scent, but if you notice a burning or chemical odor, this could indicate that the oil has broken down or is contaminated.

3. Increase in Engine Noise

When you start your car and get to hear weird noises, it is never a good sign. 

So if you notice an increase in engine noise, this could indicate that the oil has lost its lubricating properties and is no longer effectively reducing friction between engine components.

4. Decreased Fuel Efficiency

If you notice a decrease in fuel efficiency, this could be a sign that the oil has become thicker.

It is no longer flowing as freely as it should. Thicker oil can increase friction and drag, reducing engine performance. 

So get the oil changed ASAP.

5. Engine Warning Light

Last but not the least, if your engine warning light comes on, this could indicate a variety of problems. It can include low oil pressure or other issues with your oil system. 

That is why if you notice this light, be sure to have your vehicle inspected as soon as possible.

6 Maintenance Tips for Synthetic Oil

After reading all of these, you might be wondering how to take care of the synthetic oil. Well, follow these maintenance tips and your synthetic oil will remain perfect for the engine.

1. Regular Oil Changes

I tell these to everyone I know. Regular oil changes are the best way to maintain any kind of oil and engine.

 Synthetic oil has a longer lifespan than the other market oils. But it still needs to be changed regularly to ensure optimal performance and protect your engine.

Follow the recommended oil change interval for your vehicle to keep your oil in top condition. 

2. Proper Storage

Store synthetic oil in a cool, dry place away from direct heat. This will help extend its lifespan and prevent contamination.

3. Check Engine Conditions Regularly

Regularly check your engine for any signs of wear or damage, and address any issues promptly to avoid further problems down the road.

4. Use the Right Oil Filter

Here’s one thing that many people ignore: Oil filters can play a vital role for the oil itself and the entire engine.

Use a high-quality oil filter that’s compatible with synthetic oil. This will help keep contaminants out of your oil and ensure optimal performance.

5. Avoid Overfilling

Overfilling your engine with oil can cause a number of problems, including reduced fuel efficiency and increased engine wear.

So my suggestion would be that you check your oil level regularly and add oil as needed to maintain the correct level.

6. Use High-quality Synthetic oil

When selecting synthetic oil, choose a high-quality product that’s designed for your specific vehicle.

Yes, it might cost you a bit, but it will definitely ensure high engine performance as well. And high-quality synthetic oil has its own durability and lifespan, which will amaze and benefit you in the long run.

Frequently Asked Questions

1. Can I mix synthetic oil with conventional oil?

Answer: Yes, you can.

In general, synthetic oil can be mixed with conventional oil, but it’s important to use a high-quality synthetic oil that’s specifically designed for this purpose.

2. Why does synthetic oil last longer than conventional oil?

Answer: Synthetic oil lasts longer than conventional oil due to its unique chemical composition. As a matter of fact, you will be glad to know that different types of artificially created chemicals are used here. 

So synthetic oil has an overall better resistance to heat, breakdown, and contaminants compared to conventional oil. That is why it lasts longer. 

3. Can the lifespan of synthetic oil be affected by driving conditions?

Answer: Yes, the lifespan of synthetic oil can be affected by driving conditions such as:

• high speed
• heavy loads
• frequent stop-and-go driving.

Final Thought

In summary, leaving oil in an engine for a good amount of time is never a good idea. It is harmful for the engine in a lot of ways. 

You can expect a maximum of 2 years of time that synthetic oil can sit in an engine. But if it is possible, replace unused oil if it is more than just 6 months. Also, follow the maintenance tips as much as you can.

Till then, Safe Driving!