Does your engine need an upper cylinder lubricant?

We’ve seen the bottles lined up at the auto parts store: upper cylinder lubricants. Their brightly colored packaging promises increased performance and decreased wear. After all, the labels state, the top end of your engine is a vulnerable place. 

So what does the science say about this? 

Gasoline serves as an efficient degreaser and, as explained by Zachary J. Santner, senior specialist of quality at Sunoco, alcohol is an even more effective one. If you feed an older car that’s long lived on a diet of subpar gasoline a healthy dose of alcohol, Santner continues, that sudden cleaning can lead to issues in the fuel delivery system–like a clog somewhere in the works. That alcohol is simply cleaning away years of accumulated sludge. 

Unlike petroleum products, he continues, that alcohol doesn’t leave behind any residue that can provide some level of lubrication, thus allowing a metal-on-metal situation to develop. Picture valve stems that, thanks to the cleaning properties of alcohol, are now running dry. Scary stuff, right? 

These upper cylinder lubricants, he explains, add some lubrication properties into the gasoline. The products are simply mixed into the gasoline.

The big question: Should this problem keep you awake at night? 

Santner wouldn’t worry about it if running a standard pump fuel, even one labeled as E15. Go all the way up to E85, he says, and it might be something to consider depending on your setup. Still, he’s not terribly concerned about the need for adding an upper cylinder lubricant–at that point, he notes, perhaps it’s something to at least track, monitor and treat should the need arise.

So when is an upper cylinder lubricant needed? When running fuels that nearly contain all alcohol–like E98 or methanol. “When you enter these worlds of alternative fuels,” he explains, “there are considerations.” He does see a lot of drag racers running upper cylinder lubricants as these fuels are simply more prevalent in that world.

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