How long can Synthetic Oil sit in an Engine?

Discover How long Synthetic Oil can sit in an Engine.

Excellent inquiry!

Motor oil should ideally remain in an engine for a maximum of around six months.

Although unused motor oil can generally be stored for five to eight years, the effective lifespan of oil within an inactive engine is approximately six months.

Over time, old oil can become dry, and unfortunately, dry oil is unable to provide safe lubrication for your engine.

An image illustration of How long  Synthetic Oil can sit in an Engine
How long can Synthetic Oil sit in an Engine
Source: (vehq)

How long can Synthetic Oil sit in an Engine?

A common inquiry among consumers regarding synthetic oil is its longevity.

Similar to many products, the answer hinges on usage conditions and the specific type of synthetic oil in question.

Generally, synthetic oil typically remains effective for a span of 6 to 12 months.

In terms of mileage, synthetic oil is typically viable for 7,500 to 10,000 miles.

Among these factors, the duration the oil remains effective is more adaptable.

For instance, if you own a classic car driven only on Sundays, the synthetic oil in the engine may endure for up to 2 years.

Conversely, if you cover extensive distances weekly, your synthetic oil might necessitate a change every 2 or 3 months.

How long can Synthetic Oil sit in an Engine Compared to Conventional Oil?

The rising popularity of synthetic oil over conventional oil is attributed to its significantly prolonged lifespan.

While conventional oil requires replacement every 5,000 to 6,000 miles, synthetic oil, as noted, can endure up to 10,000 miles—an extension of about 40%.

In Europe, Castrol even markets synthetic oil claiming a longevity of up to 20,000 miles!

Tests conducted by the American Automobile Association, widely known as “Triple-A,” have consistently shown synthetic oil outperforming conventional oil in almost every aspect.

Consequently, engines can operate on synthetic oil for significantly more miles before necessitating a change.

How Long Can Synthetic Oil Be Safely Stored?

Experts concur that synthetic oil when stored in its original container, maintains its quality for 7 to 8 years before it undergoes deterioration.

However, this changes if the oil is poured out of its original container and stored elsewhere, as oxidation is likely to occur in such cases.

Why Synthetic Oil Lasts Longer

Synthetic oil outlasts conventional oil because it eliminates heat-induced breakdown and oxidation, preventing harmful sludge.

It remains fluid in freezing temperatures, ensuring quicker engine protection.

Synthetic oil costs more due to a complex and time-consuming refining process—almost four times that of conventional oil.

Despite the higher upfront cost, its extended engine life leads to overall savings.

Synthetic Blend vs. Synthetic Oil

A synthetic blend combines synthetic and conventional oil, offering benefits at a lower cost.

Yet, expect more frequent changes compared to pure synthetic oil, impacting long-term savings.

An image illustration of Synthetic Oil Duration in an Engine
Synthetic Oil Duration in an Engine
Source: (hips. hearstapps)


Synthetic Oil Production

  1. Laboratory Formulation: Skilled chemical engineers develop a proprietary formula for synthetic oil in a laboratory.
  2. Refinery Process: The formula moves to a refinery, where raw oil (and sometimes natural gas) undergoes a more intricate distillation and purification process compared to conventional oil.
  3. Impurity Removal: Synthetic oil undergoes additional processes to ensure molecules are nearly identical in shape and size, eliminating impurities absent in conventional oil.

Drawbacks of Synthetic Oil

  1. Higher Cost: Synthetic oil is pricier (1-2 times) than conventional oil due to its intricate manufacturing.
  2. Additive Separation: Cold temperatures can cause additives in synthetic oil to separate, potentially affecting performance.
  3. Slight Fuel Economy Reduction: Synthetic oil may lead to slightly lower fuel efficiency at highway speeds.

Conclusion on How long can Synthetic Oil sit in an Engine?

The duration synthetic oil can safely sit in an engine depends on various factors such as usage conditions, mileage, and the specific type of synthetic oil employed.

While synthetic oil generally maintains its quality for 6 to 12 months.

Mileage-wise, it can endure between 7,500 and 10,000 miles.

However, for engines with infrequent use, such as classic cars driven occasionally, synthetic oil may last up to two years.

It’s crucial to consider both time and mileage factors to ensure optimal engine performance and lubrication.

Regular consultation with a mechanic and adherence to manufacturer recommendations can guide appropriate oil change intervals for optimal engine health.

ALSO READ: Can Low Engine Oil cause Transmission problems?


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