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Proving our best high mileage protection


We bought a high mileage car, doubled its miles and only changed the oil every 15,000 miles. See how Mobil 1™ Extended Performance High Mileage motor oil held up throughout the test.


The right car for the test

To test our full synthetic high mileage motor oil, we needed to find a high mileage vehicle. We selected a popular four-door sedan, a used 2009 Honda Accord EX-L, which had 117,747 miles on its 2.4-liter 4-cylinder engine.

“We never tested a used car like this, so we didn’t really know what we’d find under the hood. How much sludge or wear would there be? Overall, how would our new formulation perform under the test conditions?”

– Aparna Subramanian, ExxonMobil engineer

According to its CARFAX® report, the Accord had at least two previous owners, 13 service history records, one open recall and one accident reported. It was primarily used as a personal vehicle in Pennsylvania and New Jersey.

Testing 15K miles of protection in a high mileage engine

The goal of the test was to see if Mobil 1 Extended Performance High Mileage oil could:

  • Protect a high mileage engine for 15,000 miles between oil changes
  • Maintain engine condition throughout the 120,000-mile test
  • Help extend engine life

The Accord, already with more than 100,000 miles on its odometer, was run 120,000 miles with oil changes being performed every 15,000 miles. A combination of test cycles simulated city and highway driving.

Test conditions for the Honda Accord

Red Honda Accord with Mobil 1™ Extended Performance High Mileage Red Honda Accord with Mobil 1™ Extended Performance High Mileage

Results you can see

At the end of the 120,000-mile test, the Accord’s engine was carefully removed, disassembled and studied. The performance of Mobil 1 Extended Performance High Mileage advanced full synthetic motor oil was measured, charted and photographed.

Oil viscosity was recorded every 5,000 miles during the 120,000-mile test. In the graph below, the upper and lower limits indicate the boundaries of oil breakdown. Notice how Mobil 1 Extended Performance High Mileage maintained stable oil viscosity by controlling oil breakdown during each 15,000-mile oil change interval.

ASTM D445: Industry standard test for measuring kinematic viscosity

Oil breakdown chart Oil breakdown chart

Kinematic viscosity is how fast a fluid is moving when a certain force is applied. The ASTM D445 test measures the kinematic viscosity of lubricants at 100 degrees Celsius; this is done by measuring the time for a volume of liquid to flow under gravity through a calibrated glass capillary viscometer. Throughout the 120,000-mile test, Mobil 1™ Extended Performance High Mileage 5W-20 advanced full synthetic motor oil demonstrated outstanding viscosity control and maintained its protective qualities.


Protection against sludge: Top deck before test vs. Top deck after test

Honda sludge comparison Honda sludge comparison

Mobil 1™ Extended Performance High Mileage 5W-20 advanced full synthetic motor oil with active cleaning agents helped prevent the formation of additional sludge and deposits.


Mobil 1 Extended Performance High Mileage proved its outstanding engine protection by delivering exceptional control of oil breakdown during the 15,000-mile oil change intervals of the 120,000-mile test. In high mileage engines, seal conditioner can help protect against engine leaks, and the seal conditioner of Mobil 1 Extended Performance High Mileage oil helped prevent any leaks from occurring during the Accord’s testing.



Engine heart with white background Mobil 1™ Extended Performance High Mileage

The lifeblood of high mileage engines.

Discover Mobil 1™ Extended Performance High Mileage, the only high mileage motor oil that guarantees 15,000 miles of protection.
Find location of Mobil 1™ Extended Performance High Mileage motor oil

Where to buy Mobil 1™ Extended Performance High Mileage oil

Use our locator tool to find stores that carry Mobil 1 Extended Performance High Mileage oil.
Mobil 1™ Extended Performance motor oil filters

The perfect companion product

For outstanding engine protection, use the Mobil 1™ Extended Performance oil filter with Mobil 1™ Extended Performance High Mileage oil.
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