2026 test5 productsEngine Oil & Fluids
Which Engine Oil Contaminant Brand Wins?
We compared 5 engine oil contaminant options head to head. Anti-Seize came out on top. See the measured results, the runner-up, the budget pick, and a link to the full test video.
Winner
Anti-Seize
Check price on Amazon
Affiliate link. We may earn a commission at no extra cost to you.
Runner-up
Sugar
Check price on Amazon
Affiliate link. We may earn a commission at no extra cost to you.
The measured results
Every number below is read straight from the test. Scroll sideways to see all measurements. Products are listed in the order they finished.
| Product | Starting compression | Runtime before test ended | Pull force to turn engine over after cooldown | Restart after test | Runtime to failure | Internal damage | Starting pull force |
|---|---|---|---|---|---|---|---|
| 1Anti-Seize aluminum anti-seize lubricant | close to 50 psi on this engine, versus about 45 psi baseline on the other four engines, ambiguity kept verbatim rather than treated as an error | 118 minutes, almost 2 hours, still no engine smoke and sounding good, test ended by the presenter rather than by engine failure | not tested | not tested | not tested | not tested | not tested |
| 2Sugar | very close to 45 psi | just over an hour, sounding perfectly fine throughout, test ended by the presenter rather than by engine failure | 31.4 lb, up from a 22 lb baseline on a new engine | took two attempts but started and ran normally | not tested | not tested | not tested |
| 3Sand dirt contamination | 45 psi | not tested | not tested | not tested | just over 2 hours, outlasting the metal shavings engine's roughly 100 minutes | valve lash about three times normal, a lot of aluminum glitter in the drained oil, camshaft wear present but less severe than the metal shavings engine, connecting rod cap worn but without deep grooves, moderate piston scoring, cylinder wall described as not looking too bad compared to the metal shavings engine | not tested |
| 4Steel Shavings metal shavings contamination | about 45 psi | not tested | not tested | not tested | very close to 100 minutes; developed a knock around 11 minutes, intensified through 35 minutes, began smoking badly around 1 hour 10 minutes | the connecting rod cap's oil slinger arm broke off during the test, rod cap interior and big end badly damaged, deep scratches on the piston ring and crankshaft, deep gouges in the cylinder wall, visible camshaft wear, heavy carbon buildup on the exhaust valve and spark plug | about 22 lb before the shavings were added |
| 5Valve Grinding Compound | very close to 45 psi | not tested | not tested | not tested | 2 minutes 7 seconds, developed an engine knock within about 1 minute of starting, heavy vibration caused the test stand to shift | by far the most damaged cylinder of any engine tested, piston rings completely seized, connecting rod cap destroyed, big end badly damaged, camshaft damage; engine would not restart afterward even with starting fluid | not tested |
How it was tested
- sustained running time until engine failure or test conclusion with each substance added to the crankcase of a new 212cc Harbor Freight Predator engine using Shell Rotella T6 15W40 oil
- compression reading in psi before and after testing
- force in lb required to turn the engine over via pull starter, before and after testing
- post teardown internal inspection of the spark plug, piston, piston rings, cylinder wall, camshaft, connecting rod, and valves
“Clearly, anti-seize is the least destructive additive yet.”