What Happens When You Replace Engine Oil With WD-40: A Ford Probe’s Fiery Demise

A YouTube channel called Life OD took a beater Ford Probe with a naturally aspirated 2.0-liter inline-four and drained the engine oil. Instead of adding proper engine oil, they poured WD-40 into the sump and then put the car through several abuse scenarios: burnouts, repeated redlining while moving, and finally a stationary full-throttle run in neutral.

At first the engine behaved better than you'd expect. It survived a big burnout and multiple high-rev episodes while driving. The testers note that some residual conventional oil probably remained in the engine, which likely helped the engine limp along longer than it otherwise would have.

The final test was more extreme: with the car stationary, they started the engine and held the throttle wide open. The engine bounced off the rev limiter for roughly three-and-a-half minutes before it finally died. During that period the exhaust and surrounding components became red hot, and a large fire developed. The flames persisted as the engine ran and then failed.

Why it failed (what the video shows and the likely mechanics)

• The engine lasted longer than many viewers might expect, which the crew attributes to leftover conventional oil in the engine before the WD-40 fill.
• High-rev, on-the-move driving stressed the engine but did not immediately produce catastrophic failure.
• Stationary full-throttle revving vastly reduced cooling effectiveness and precipitated the engine's final, fiery failure.

• Do not use WD-40 in place of engine oil. It is not formulated to provide the sustained lubrication, film strength, and heat-management properties required inside a running internal-combustion engine.
• If you smell burning oil, see smoke, or notice abnormally high temperatures or red-hot components, stop driving immediately and move to a safe location if possible.
• Regularly check oil level and use the manufacturer-specified grade and viscosity. Residual oil can mask the immediate consequences of a wrong fluid, but it will not prevent cumulative damage.

The video is a single, extreme experiment on one car and shows what can happen under those specific conditions. It demonstrates that replacing engine oil with WD-40 can lead to rapid, catastrophic failure and fire when the engine is driven hard, especially while stationary and rev-limited. It does not quantify how long different engines might take to fail under different loads or temperatures.

The test is a clear demonstration that WD-40 is not an engine oil substitute. Even if a motor keeps running for a while, improper lubrication plus heat buildup can trigger destructive failure and fire. Use proper engine oil and stop the engine at the first sign of overheating or burning.