Auto additives are big business, but do they work?

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Richard Perry.

■ By Richard Perry / Contributed

Greetings from the Hemet Car Guy

I’ve just turned 54, and I must admit I am slowing down a bit. My beautiful wife makes sure I take vitamins and supplements to combat Father Time. I don’t know if they work or not, but I follow her direction. However, this got me thinking about all the automotive additives you see in auto parts stores. I know it’s big business, but do they work or are they the equivalent of automotive “snake oil”?
If your car is older and starting to show its age, it’s natural to wonder if it doesn’t need a little extra something to give it more zip and performance. While it is important to take care of your car and follow the manufacturer’s recommendations on maintenance, don’t be tempted by snazzy advertisements stating that your car needs additives. I’ve talked with a number of mechanics and they shared some great information that I’ll pass on to you.
Here are three common additives you might be enticed to buy and why you don’t need them.

Gas additives
The claims are big—improve performance, reduce emissions, and improve your gas mileage! The fact is none of these additives are necessary if your car is properly maintained.
Those designed to reduce knocking may actually do so, but using them simply masks the problem, it doesn’t fix it. Engine knocking is a sign that your car needs a repair! So instead, see your mechanic to rectify the underlying problem.
Tests on additives designed to clean your fuel system have not been shown to make any significant difference in reducing corrosion or deposits and don’t improve performance. Tests on additives that claim to improve gas mileage never have shown significant improvements, at least according to the Environmental Protection Agency. The only gas additive that has proven useful is a stabilizer, but this should be used only in cars that aren’t driven very often.

Extended-life radiator coolants

The proper mix of radiator coolant and water is essential to keeping your engine cool in both hot and cold temperatures as well as to prevent corrosion. Some coolants are promoted as extended life, and they use a different type of corrosion inhibitor.
While the claims are valid, automakers designate their cars to use one type of coolant or the other, so don’t assume an extended life coolant is better for your car. Most important, never mix the two types of coolants as this will affect the corrosion inhibitors. Your owner’s manual will tell you which type is recommended. It’s best to follow the manufacturer’s schedule for draining and replacing the coolant. Flushing the coolant according to schedule is important, but more frequent flushes are a waste of money.

Oil additives
With an older, high-mileage car, it’s easy to believe the engine is getting tired and needs an additive to improve performance or reduce wear. But oil additives simply don’t work. In fact, they may actually harm your engine, according to numerous independent testing agencies.
The Federal Trade Commission has gone after several companies that sell these additives for false advertising. The dreaded engine sludge that causes an engine to run poorly or even seize up is a rare occurrence and typically happens only when oil changes have been neglected or if the car has been driven a lot with an extremely low oil level.
Unfortunately, there really is no magic potion for your older car. Nothing beats good, regular maintenance to keep your older car running.
With that said, I think I’ll call my doctor and get my regular annual checkup before my wife trades me in for a younger model.

Meanwhile, here’s to good driving and good health in 2018.

The Hemet Car Guy

Richard Perry is the Hemet Car Guy and owner of VIP Autos in Hemet. For more information, visit

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