It’s one of those crazy thoughts which has really no way for the average person to go about solving: what happens if an engine runs without any oil flowing through it whatsoever? Thankfully, Jason Fenske from Engineering Explained is back to do it for us and cure the curiosity at large. You know, rather than curiosity killing a crankshaft on someone else’s watch.
To see the effects, Jason once again hooked up his handy-dandy thermal camera to see how heat and temperatures played with a 212-cc air-cooled, single-cylinder engine. On the left, you will see the engine running with oil. On the right, the same identical engine runs sans lubrication. The engine running with no oil was filmed 24 hours after the engine was run with oil to ensure it cooled down to resting temperatures. This is science, after all.
Jason highlights five points monitored for the engine: the crankcase below the level where oil will rest, on top of the crankcase where no oil will rest, the engine block, the exhaust pipe exiting the cylinder, and the valve cover.
With those areas identified, the engines run for 15 minutes to see what may happen. The experiment also took care to ensure there would be no reason the engine without oil would be hotter than the one with oil. To our surprise, the engine without oil consistently stays cooler than the engine with oil, even after Jason admits the choke was closed on the engine minus oil for over two minutes.
Still, the engine on the right has plenty of time to show signs of increased heat, which it never does. It’s not the big bang we were expecting. However, internally, it’s a very different story.
Removing the crankcase shows sludgy, black oil leftover after the engine was drained a day before. And what are those shiny sparkles in the oil? Metal shavings, thanks for asking. Not good.
The connecting rod cap from the crankshaft also shows serious signs of wear after only 15 minutes. Its surface is scored and less shiny compared to a well-lubricated example.
What’s the moral of the story? Always make sure your car's engine has enough oil. And make sure the oil is changed regularly—along with the filter.