Synthetic oil vs Conventional oil

high mileage oil analysis

See 540 Rat the Mechanical Engineer .See his Engine Oil Analysis done on High Mileage oil

Valvoline Max Life - High Mileage Motor Oils Test

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​High Mileage oils are formulated for older engines with over 75,000 miles on them. And High Mileage oils include “Seal Swell” chemicals to help reduce oil leakage in those older engines.
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Below is how 5 different High Mileage oils ranked just among themselves, regarding wear protection capability, after they were tested.

The Wear protection reference categories are:
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• Over 105,000 psi = INCREDIBLE wear protection
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• 90,000 to 105,000 psi = OUTSTANDING wear protection
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• 75,000 to 90,000 psi = GOOD wear protection
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• 60,000 to 75,000 psi = MODEST wear protection
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• Below 60,000 psi = UNDESIRABLE wear protection

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5w30 Valvoline MaxLife High Mileage

​1. 5W30 Valvoline MaxLife High Mileage, API SN, synthetic blend = 108,045 psi

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5W30 Pennzoil High Mileage Vehicle

​2. 5W30 Pennzoil High Mileage Vehicle, API SN, conventional = 102,402 psi

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5W30 Castrol GTX High Mileage

3. 5W30 Castrol GTX High Mileage, API SN, synthetic blend = 91,404 psi
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10W30 Quaker State High Mileage,

4. 10W30 Quaker State  High Mileage, API SL semi-synthetic = 90,226 psi
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5W30 Mobil 1 High Mileage

​5. 5W30 Mobil 1 High Mileage, API SL, synthetic = 88,081 psi

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​As you can see, these oils all performed very well, even though the top 3 are modern low zinc API SN oils. And that is even more proof that oils DO NOT need high zinc levels to provide excellent wear protection.