Should You Use Synthetic Oil in Older Cars? The Facts

If you’re a classic car owner, you likely want the best protection for your engine. So it might be a case that you’re considering switching from conventional oil to synthetic oil.

There is no doubt that Synthetic oils contain a range of additives designed to keep your engine clean. Unfortunately, some older engines may experience issues as a result.

Conventional vs Synthetic Oil

When it comes to motor oil, there are plenty of choices available. Some are easier to locate than others, but ultimately the right choice for your vehicle and driving habits must be taken into consideration.

Conventional motor oil is the most widely-used option and has been around for years, boasting a reputation as being easy to locate at reasonable prices. On average, conventional motor oil allows you to go approximately 3,000 miles between oil changes depending on your driving style and environmental conditions.

Synthetic oils, on the other hand, are man-made and much more refined. This makes them last longer and work better at both high and low temperatures.

They also help prevent sludge buildup, which is especially prevalent in older engines. If left untreated, this gunky residue can clog passages and lead to engine damage.

Should You Use Synthetic Oil in Older Cars

Should You Use Synthetic Oil in Older Cars?

It is safe to say that many owners of newer cars, trucks and SUVs are switching to synthetic oil due to its increased longevity and superior engine performance and protection.

Synthetic oil is also more resistant to breaking down and evaporating in extreme temperatures, making it an ideal choice for drivers who spend time outdoors or who use their vehicles for towing.

Another benefit of synthetics is their resistance to sludge and buildup within your engine. This helps to keep it running efficiently, potentially saving you from expensive repairs over time.

However, if it is a case where your car has 75,000 miles or more on it, switching to Mobil 1 High Mileage synthetic oil could be beneficial. These oils have been specifically designed for older vehicles in order to help extend the life of your vehicle by keeping seals and gaskets from becoming brittle.

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Benefits of Synthetic Oil

Synthetic oil is increasingly being used in newer cars for various reasons, from extending component life to cutting down on maintenance expenses. But some may still be unsure whether it’s necessary to switch from conventional oil to synthetic oil in their older vehicles.

In most cases, synthetic oil offers some distinct advantages over conventional motor oil that may be beneficial for older vehicles. Here are some of the most frequent reasons why some choose synthetic over conventional oil:

Improved Heat Tolerance

Synthetic oils have been engineered to resist breakdown at high temperatures, helping them last longer and perform better for heavy-duty jobs.

Superior Cleaning Power

Synthetics are excellent at eliminating gunky residue that can clog oil passages and cause severe engine damage, particularly in older engines prone to sludge accumulation.

Risks of Using Synthetic Oil in Older Cars

Synthetic oil has its advantages for older cars, but there can also be drawbacks. For one thing, synthetic oils clean the engine better but can be rough on seals within the engine, which can cause the seal to wear down and begin leaking.

Another potential downside of synthetic oil is that it may reduce fuel economy. This occurs because the engine doesn’t get a complete heat cycle, resulting in a more gradual flow of oil through it and lower lubrication levels.

To determine whether synthetic oil should be used in your older car, consult a mechanic who is familiar with the vehicle. They can advise you on which type of oil to use and how often it should be changed.


Generally, if your engine is old and you want to extend its life, switching to synthetic oil may be worth considering. However, be sure to understand any potential risks before making a final decision.