If you’ve had an oil change recently, you’ve probably been asked whether you want to use conventional motor oil or synthetic motor oil. If you’re not an expert on cars, you might have no idea which one makes the most sense for your vehicle’s needs.

The truth is, there isn’t one right answer to this question, because older vehicles have different needs than newer models. In general, however, the older your car is, the more likely you’ll do better with conventional motor oil.

Why is that the case? Here’s a look at the two options and which makes the most sense.

Temperature Affects Viscosity

In general, synthetic engine oil performs better at extreme temperatures than motor oil made from crude oil. And if you’ve ever spent much time in Canada, you know that winter is about as extreme as it gets here. So, at first glance, that makes it seem obvious to Canadian consumers that a high-performance synthetic blend is better for their car.

Not so fast. The higher lubrication is great for newer cars that are made of synthetic oil. But for older models, synthetic oil can flow a little too smoothly for what they’re used to receiving. These cars were made for regular oil, and they’re designed to operate with conventional motor oil even at low temperatures. For them, even though the engine performance is supposed to be improved, the smoother flow can actually cause gears to grind and reduce engine performance.

High Mileage Doesn’t Always Means Synthetic Is Bad

Remember, reading the owner’s manual is always the first step to getting the most out of your car. Not every older vehicle was designed with crude oil in mind. Some vehicles were designed to work with synthetic oil and simply have high mileage because of excessive use from their owner. In these cases, you’ll get better protection and performance with synthetic motor oil at each oil change.

You’ll also usually clean out your engine and improve your fuel economy by using synthetic oil in these cars. That’s because synthetic motor oil also carries additives that are designed to prolong the life of your car. Scheduling regular oil changes helps get these additives into your vehicle’s system, which leads to less engine wear and less buildup in the car’s engine.

Cheaper Long-Term Costs

Costs are always important to consider when vehicle maintenance is part of the equation. With synthetic motor oil, you’ll usually encounter a lower cost at each oil change, simply because your car can go longer in between oil changes.

With fewer contaminants in the car’s engine system, you’ll be better equipped to handle any driving conditions. You’ll also see your engine parts last longer, which means a lower long-term cost for repairs.

Before you decide which motor oil makes sense for your car, be sure to consult your owner’s manual to ensure your car is designed for synthetic oil. If it is, you’ll likely save money in the long run.