Testing different oils over 4 years and 1 MILLION miles

Summary

Ben and John from Gears and Gasoline visit Valvoline’s powertrain testing lab to inspect two Ford Explorer engines, each with 500,000 miles. The only difference: one used Valvoline conventional oil, the other Valvoline synthetic. They dismantle the engines, comparing wear, varnish, and performance to see how the oils impacted the engines over time. Despite some minor issues, both engines performed remarkably well, though the synthetic oil engine showed significantly less varnish and wear. Their test highlights the durability and protection of Valvoline’s synthetic oils in high-mileage engines.

Takeaways

• 🔧 Two 2.3L 4-cylinder engines, each with 500,000 miles, were tested at Valvoline's powertrain lab under identical conditions, with one using conventional oil and the other using synthetic oil.
• 🛢️ Both engines underwent 10,000-mile oil change intervals, following Ford's recommended service intervals, and were tested with the same fuel, outside temperature, and other conditions.
• 🧐 The key difference between the two engines was the type of oil: one used Valvoline conventional oil, and the other used Valvoline full synthetic oil, but they were not immediately identified.
• 🔍 During disassembly, the synthetic oil engine showed less varnishing, meaning less buildup of deposits, while the conventional oil engine had significantly more varnish and sludge.
• 📊 Despite the varnishing difference, both engines showed good wear and tear performance, meaning the metal components showed minimal damage even after 500,000 miles.
• ⚙️ The conventional oil engine had more issues with carbon deposits and sludge, which can lead to engine inefficiencies such as sticking parts and overheating.
• ❗ Both engines had minor failures during testing, such as a wastegate actuator and catalytic converter issues, which were repaired, but these did not impact the overall oil performance evaluation.
• 🔩 The engines were evaluated based on their wear surfaces, sludge buildup, and deposit ratings, showing better protection and cleanliness from the synthetic oil.
• 🚗 The synthetic oil engine had fewer cold-stuck piston rings, a common failure point that can reduce compression and engine performance, with the conventional engine showing more of these issues.
• 🎯 Overall, the synthetic oil demonstrated better long-term performance in terms of keeping the engine cleaner and reducing deposit formation, while both oils maintained good wear protection.

Q & A

What was the purpose of the Gears & Gasoline visit to the Valvoline powertrain testing lab?

Ben and Ben from Gears & Gasoline visited the Valvoline powertrain testing lab to examine two engines, each with 500,000 miles on them, to compare the performance of Valvoline standard conventional oil versus Valvoline full synthetic oil.

What engines were being tested in this experiment?

The engines being tested were small 2.3L 4-cylinder engines, commonly found in Ford Explorers, each making around 280 horsepower.

What is the main difference between the two engines being tested?

The primary difference between the two engines is that one was running on Valvoline standard conventional oil, while the other used Valvoline full synthetic oil for the entire duration of the test.

How often was the oil changed during the test, and why is this significant?

The oil change interval for both engines was set at 10,000 miles, which is the service interval recommended by Ford. This is significant because it represents a realistic oil change schedule for the average consumer.

What were some of the key observations when dismantling the engines?

Key observations included differences in varnish and wear. The synthetic engine had significantly less varnish and buildup, while the conventional engine showed more varnish, though both engines still exhibited good wear performance.

What are the potential downsides of varnish buildup in an engine?

Varnish can insulate engine parts, causing them to run hotter and potentially leading to issues like parts sticking, which can reduce engine performance and efficiency.

Did either engine experience any significant failures during the 500,000-mile test?

Both engines experienced some minor failures, including a wastegate actuator failure on one engine and catalytic converter failures on both. Additionally, one engine had a front seal leak, and the other had a rear main leak.

What is bore polish, and how was it observed during the teardown?

Bore polish refers to areas of the cylinder bore that have been polished to a shiny finish by the piston rings. During the teardown, a small amount of bore polish was observed, indicating good combustion in both engines.

How did the carbon deposits compare between the synthetic and conventional oil engines?

The engine running conventional oil had more carbon buildup on the piston tops and valves, leading to seven cold-stuck rings. The synthetic oil engine had significantly fewer deposits and only one cold-stuck ring.

What is the overall conclusion from this engine oil comparison test?

The synthetic oil engine performed better overall, with less varnish, fewer carbon deposits, and only one cold-stuck ring. However, the conventional oil engine still showed good wear performance, despite more varnish and carbon buildup.