Bottled Magic or Snake Oil? The Truth About Additives


(Illustration: Yahoo Autos.)

Fix your engine! Cure your transmission! Help your oil get … more oily!

Auto parts stores are loaded with products that seem to handle every automotive malady. You name it, and the cure’s there in a beautiful plastic bottle! 

For only a few bucks (and a prayer) it seems like you can drive home with the perfect fix to your car’s less-than-perfect problems. Just a few minutes with a funnel, and your tired beater will be tap-dancing like a new car in no time.

If only life were this easy — especially for those of us who have a car that needs a major repair in the near future. 

What do I know? I have been responsible for liquidating over 10,000 vehicles a year for an auto finance company as well as running my own car dealership near Atlanta for well over a decade. When folks ask me about one of these oily witches brews, I always tell them these three simple words in three distinct languages.

No! Nein! Nyet!

There isn’t a single auto repair shop I know of that stocks these items. Wholesale auctions that liquidate millions of vehicles nationwide every single year? Won’t find them there, either. Auto dealerships also avoid these products like the snake oils that they are for one simple reason:

They don’t work.

Few people outside the auto industry realize that manufacturers and oil companies hire small armies of chemical engineers to find the optimal additives needed to make your vehicle run as well as possible, for as long as possible. In turn, they work with the engineers who design your car’s engine and transmission so that it can endure for the long haul. That’s all they do. Unfortunately there’s one incurable problem in that equation. 

Marketing. Aftermarket oil additive companies spend a tremendous amount of money trying to get you to use products that are supposedly slick, viscous, and improve fuel economy. Even though many of these companies have been fined millions of dollars by the Federal Trade Commission for making these false claims, it doesn’t matter. Another company or product pops up with similar claims, and the legal process starts anew. 

Just like diet pills that are glorified tic-tacs, and health aids that are at best a placebo effect, these companies are trying to outperform a massive number of well-educated chemical engineers and other industry experts through glorified shill marketing and nice shiny bottles. 

At least that’s been my professional experience. But maybe I’m wrong? To figure out if there may be any benefit, at all, I interviewed Eric Johnson, who is the lead industry liaison of engine lubricants & fuels for General Motors. 

Q: Should additive packages, apart from those recommended specifically in your owner’s manual, ever be used on a GM vehicle?

Eric Johnson: GM’s stance, and I don’t think it differs from other manufacturers, is that the engine oils we approved are “fully formulated” and therefore do not require any additional additives.

Q: Are you aware of any unique chemicals or additives that are offered by other companies that don’t currently work with GM, that could supposedly enhance the motor oil you put into your vehicle?

EJ: We haven’t come across any. Frankly the best we’ve seen is no harm.

Q: Would you ever recommend these products to a friend or family member?

EJ: No. Being in the oil industry on both sides, I have known a lot of really talented folks (who) work on the engine oil side, and on the manufacturer’s side. A lot of work has gone to construct and develop these engine oils, and they already do what they’re supposed to do.

Q: But what about stop-leak additives? Do any stop-leak products offer any real added benefit to older vehicles that may have any type of leak?

EJ: First and foremost, certainly in the last 10 years, you don’t want to put in anything that changes your oil’s viscosity. Adding liquids that simply don’t belong there can change how your engine functions and it’s longevity. When an OEM [automaker] makes a recommendation for a specific viscosity, for example 5W-20, they do so because the engine has been specifically designed for it.   

With regard to stop-leak, there may be any number of reasons why an engine could consume oil. Unless you take the engine apart to figure out why it’s consuming oil, you’re guessing at a cure that may not cure it. In today’s vehicles especially, you risk damaging the entire engine. 

That last question is what interested me as someone who owns a Jeep Cherokee that is now over 20 years old. 

I could have put stop-leak in my leaky radiator, but I replaced it instead for a little over $100. I could use a product that temporarily swells the rear main seal which is now leaking pretty bad, but I’m going to spend $250 to replace that seal and make it right. 

I get that there are situations where you can’t afford the repair and that bottle is the last chance before the car becomes a junker. I was there before I knew much about cars.

But I realize now that if you put the right oils and parts for any vehicle these days, and take care of the little problems before they become big, your vehicle can last for an amazingly long time.

So do yourself a big favor. When you see some snake oil at the auto part store promising you things that not even the most advanced lubricants can do these days, save your money. Better yet, repair your car the right way and invest in a healthy future without car payments. You’re already putting the right stuff in your car. 

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