Motor Oil May 2019 Test: Which Brand Wins?
In our May 2019 test we compared 4 motor oil options head to head. Kendall came out on top. See the measured results, the runner-up, the budget pick, and a link to the full test video.
Castrol
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The quick take
The short version of why each pick lands where it does, built straight from the measured results.
“While Castrol won the evaporative loss test, Kendall won the lubricity test and the oil flow test for both new and cooked oils. So, it'll advance in the series.”
The measured results
Every number below is read straight from the test. Products are listed in the order they finished.
Specs
- 1Kendall GT-1 Max full synthetic
full synthetic, API SN and ILSAC GF-5 licensed, liquid titanium protection additive, made by Phillips 66 Company, designed for gasoline passenger cars/light trucks/SUVs in severe or normal driving conditions
- 2Castrol Edge Extended Performance
full synthetic, fluid titanium technology, guaranteed protection up to 15,000 mi or 1 year, API SN resource conserving, not recommended for severe service (racing, frequent towing/hauling, commercial use, extremely dusty/dirty conditions, excessive idling)
- 3Quaker State Ultimate Durability Full Synthetic 5W-30
SAE 5W-30, full synthetic, Dexos 1 Generation 2 approved, meets or exceeds ILSAC GF-5 and API SN Plus, marketed for unsurpassed wear protection, extended engine life, oil breakdown resistance, extreme temperature protection
- 4Valvoline Full Synthetic
full synthetic, claims 50% more wear protection than Valvoline's own conventional oil, Dexos Generation 2 approved, meets or exceeds ILSAC GF-5 and API SN Plus; self-rated on the bottle at 3 stars wear protection, 4 stars extreme temperature protection, 3 stars cold start protection, 3 stars fuel efficiency, 4 stars deposit-formation prevention, 4 stars sludge buildup prevention
Lubricity Test
- 1Kendall GT-1 Max full synthetic
won against Castrol, 'edging out Castrol by a very small margin' (wear-scar/bearing test, about 10 minutes)
- 2Castrol Edge Extended Performance
lost to Kendall by a very small margin
- 3Quaker State Ultimate Durability Full Synthetic 5W-30
won against Valvoline; narrator notes both brands' anti-wear additives 'did better than average' but 'Quaker State walked away with the win'
- 4Valvoline Full Synthetic
lost to Quaker State
Evaporative Loss Test
- 1Kendall GT-1 Max full synthetic
started at 417.1 g, ended at 415 g, a loss of 2.1 g (lost this test to Castrol's 1.84 g loss)
- 2Castrol Edge Extended Performance
started at 442.27 g, ended at 440.43 g, a loss of 1.84 g; won this test against Kendall's 2.1 g loss
- 3Quaker State Ultimate Durability Full Synthetic 5W-30
started at 423.46 g, ended at 422.27 g, a loss of 1.19 g - the lowest evaporative loss of all four oils tested in this episode; won this test against Valvoline's 2.61 g loss
- 4Valvoline Full Synthetic
started at 407.25 g, ended at 404.64 g, a loss of 2.61 g - the highest evaporative loss of all four oils tested in this episode
Oil Flow Test
- 1Kendall GT-1 Max full synthetic
new Kendall won the race outright: crossed the finish line about five molecules ahead of new Castrol, less than half an inch ahead of cooked Kendall, and about an inch and a quarter ahead of cooked Castrol
- 2Castrol Edge Extended Performance
new Castrol finished second (about five molecules behind new Kendall); cooked Castrol finished last, about an inch and a quarter behind new Kendall
- 3Quaker State Ultimate Durability Full Synthetic 5W-30
lost to Valvoline, which took the checkered flag by a full inch over Quaker State
- 4Valvoline Full Synthetic
won against Quaker State by a full inch; described as getting 'out of the gate in a hurry' and 'too fast for the competition'
How it was tested
- lubricity test (bearing wear-scar and weight-loss measurement, about 10 minutes per oil, film strength/anti-wear performance)
- evaporative loss / heat resistance test (200 g of oil heated to about 375 to 400F for 2 hours, weighed before and after for evaporative loss, informal analog to the Noack volatility test)
- oil flow race test on new oil and on oil that had been exposed to heat (cooked), comparing viscosity/flow speed down a track
“While Castrol won the evaporative loss test, Kendall won the lubricity test and the oil flow test for both new and cooked oils. So, it'll advance in the series.”
Data notes and caveats
Dual-matchup bracket episode: TWO separate head-to-head pairings are bundled in one video. The title-framed primary matchup (Kendall vs Castrol) drives the top-level winner/runnerUp fields (Kendall advances 2 tests to 1). A second, independent matchup (Quaker State vs Valvoline) is also decided in this video: Quaker State advances 2 tests to 1 ('Quaker State won both the lubricity test along with the evaporative loss test and will advance in the playoffs'). Preserved in the Quaker State and Valvoline product entries; flagging so a future build can split this into two separate head-to-head pages if needed.
