Vegetable oil as a replacement for motor oil? It’s been tested, here’s how well it worked – Jalopnik

A gallon of full synthetic motor oil typically costs less than $10, but it could be the only thing standing between you paying thousands for a new engine. To help prevent this, oil companies naturally spend significant amounts of time and money fine-tuning their products for optimal performance, and automakers just as carefully design their engines to run on one specific quality of slick stuff. None of this has stopped people from replacing motor oil with vegetable oil – and then helpfully posting their results online.

The real-world outcome was also surprisingly positive. If you start doing your own research, you’ll find that the experts explicitly say that putting vegetable oil in a car engine is a terrible idea and should never be done. But then the team arrived Project farm I tried running a lawn mower engine after filling it with vegetable oil instead of motor oil, but there really wasn’t any immediate problem. The only serious problem noted was that vegetable oil almost froze solid at extremely low temperatures, but the engine oil retained its viscosity. That said, if you watch the video yourself, you will notice that the cylinder and piston head appear noticeably dirtier after using vegetable oil than before.

YouTubers have also successfully revved engines in pressure washers and motorcycles with vegetable oil, at least for the duration of the videos. However, when someone tried it with a real car, a beat-up Hyundai Tiburon – one of those cars you probably forgot existed – the poor thing threw out a fishing rod, because The drive reported.

The aforementioned difference in viscosity between motor oil and vegetable oil is part of what makes the latter a poor choice for lubricating any part of a car’s drivetrain. The chemical composition of vegetable oil means that at higher temperatures it is less viscous and thinner than motor oil. So when things heat up in the engine, the vegetable oil breaks down more quickly and cannot create enough of a barrier between the engine parts to keep the parts properly lubricated. At the other temperature extreme, as Project Farm discovered, vegetable oil is more viscous than motor oil; in the video it turned into a lump of greasy liquid. Try starting a cold engine with that stuff in there, the oil won’t be able to flow where it needs to go.

Moreover, motor oil is not pure oil. It also contains additives that not only help optimize viscosity, but also detergents and dispersants to keep the engine clean and anti-wear agents and friction modifiers to help prevent metal-on-metal contact. Individual additives can protect against rust and corrosion and ensure healthy engine seals. Foam or air bubbles can also cause problems if they develop in your oil, so most motor oils come with an additive for that too. The effects of using these types of additives are unlikely to be visible on a short YouTube video. And to be clear: we are talking about additives that are already in the engine oil, and not about aftermarket additives such as Seafoam and Lucas.

One of the reasons why so many drivers seem interested in using vegetable oil in their engines may be because they’ve heard that it can be used as a fuel – and for diesel-powered cars, that may be true. The secret here is that diesel engines operate on slightly different principles than their gas counterparts: a gasoline engine requires a spark to ignite, while a diesel engine relies on compression ignition. Simply compressing the diesel fuel and air in the cylinder is enough to raise the temperature to the ignition point. And the same can happen with vegetable oil, which is also an important source of biodiesel.

But to make vegetable oil/biodiesel compatible with a car engine for everyday use, both the fluid and the hardware require some adjustments, especially to achieve the right viscosity for proper lubrication and atomization – which refers to how the fuel is broken up into small droplets to mix with the air for better combustion. It is now so popular that even Cummins engines can run on biodiesel.

Returning to the real world, Consumer Reports evaluated a 2002 Volkswagen Jetta TDI running on diesel fuel, biodiesel, a popular diesel blend containing 5% biodiesel and pure vegetable oil. The Jetta ran well on vegetable oil, but had the lowest highway fuel economy and the highest amount of unburned hydrocarbon emissions (compared to the Jetta running on other fuels).