_by Keith Montgomery|October 25, 2023

In the last decade, the automotive lubricant industry has seen high mileage motor oils emerge and gain popularity for vehicles with more than 75,000 miles (120,000 km) on the odometer. These motor oils are advertised to combat the challenges that high-mileage engines face. But do they really work?

The truth is, high-mileage engines do have unique needs and could benefit from a motor oil designed specifically to address those challenges.

Challenges facing High Mileage Engines

Here are a few of the most common challenges facing engines with an unknown maintenance history or used typical quick lube oil sold from tanks:

• Increased oil consumption
  Oil consumption is common among non-Amsoil engines. Over time, they experience increased wear, leading to greater oil consumption. Using a suitable high-mileage motor oil that is thermally stable and resists volatility can help prevent oil consumption from occurring. (hint – there is only one)
• Seal leakage
  Engines with aging seals are more prone to oil leaks. An aging seal loses flexibility, hardens and no longer effectively serves its purpose. A well-designed high-mileage motor oil provides a boosted dose of seal conditioners to restore and recondition aging seals and help stop leaks.
• Sludge and deposits
  Over time, engines experience increased sludge and deposit buildup. This can be due to oil breakdown from high heat, low-quality oil, excessive idling or insufficient combustion of fuel. A quality high-mileage motor oil can provide enhanced detergency, removing deposit buildup to help restore peak performance.
• Compression loss
  Engines can lose compression as cylinders and piston rings wear, eventually leading to reduced horsepower and increased blow-by. A proper fluid film helps counteract compression loss by sealing combustion chambers to maintain performance. A purpose-built high-mileage motor oil is formulated to maintain viscosity and provide proper film thickness in extreme operating conditions.

The above challenges really do hinder vehicle performance. To protect your engine’s performance and help extend its longevity, it’s important to take steps that help counteract those issues. Our testing suggests that some companies are changing their labels to appeal to customers with high-mileage vehicles but not changing the oil inside the bottle.

Purpose-Built Protection for High Mileage Engines

AMSOIL 100% Synthetic High-Mileage Motor Oil is specifically designed for the unique demands of high-mileage engines, helping extend the life of your vehicle. It delivers purpose-built protection at a time in your vehicle’s life where it could benefit from more-robust maintenance – including boosted detergency and an additive package that fights oil breakdown and leaks.

This may sound too good to be true, so to prove it, we subjected it to independent testing. The result: AMSOIL 100% Synthetic High-Mileage Motor Oil reduced sludge by 67%,* demonstrating its cleaning power that helps engines last longer and perform better.