Top Five Car Maintenance Myths

Today’s blog theme is car maintenance myths. When we talk about myths, we’re not making reference to the characters who populate ancient Greek and Roman mythologies, like Apollo, Hercules and Medusa. In this context the word myth has evolved to simply mean “beliefs that are not true.”

Here’s something that I learned recently wasn’t true: All my life I’ve heard people say that we only use 10 percent of our brain power. If we could liberate our minds, we could move mountains with our untapped brain energy. Self-help guides and others have repeated this so often that it’s assumed to be solid truth.

But is it? Modern neuroscience has learned that different parts of our brains have different functions. There is no real “untapped” power source residing in that grey matter. All the various parts of the brain have their own specialized functions.

In the same way, many of today’s car-maintenance myths are simply statements that have been repeated so often that everyone assumes they’re true. In the past, some maintenance tips were indeed conscientious practices, but over many decades the technology has changed and what was useful long ago is no longer valid.

As I scoured the web for lists of car maintenance myths, I found plenty. The following five stood out the most to me.

Myth #5: Air conditioning hurts fuel economy

Granted, this doesn’t necessarily fall under “car maintenance”, but it’s still a popular misconception. According to Consumer Reports, “There has been much debate about whether to drive with the air conditioner on or keep the windows open in order to save gas. Using the A/C does put more load on the engine, but in our tests, we found just a slight decrease in fuel economy and no measurable difference when opening the windows (open windows do increase aerodynamic drag). However, using the A/C helps keep the driver alert and more comfortable, which is safer for everyone on the road. We say, just use the A/C and don’t worry about it.”

Myth #4: Warm up your car for several minutes before driving

I can’t tell you how many times I’ve heard people say you need to warm up your car for several minutes before driving. I haven’t done it in years myself, but notice that quite a few others do. According to Stephen Mraz at, “Driving the car is the fastest way to warm up a modern engine, and the sooner it warms up, the sooner it delivers the best mileage and performance. And don’t rev the engine during the first few miles.” In other words, don’t waste time or gas running your car for several minutes before you take off in the morning.

Myth #3: Inflate tires to the pressure shown on the tire’s sidewall

Inflating tireThis one also gets cited by Consumer Reports. I don’t know how often you check your tire pressure, but if you’re like most, it’s probably only when the tire looks a little low. When I used to go to the “Free Air” pump at the gas station (I now have an air compressor at home), I always aimed for the psi stated on the side of the tire.

Here’s what Consumer Reports says: “The pounds-per-square-inch figure on the side of the tire is the maximum pressure that the tire can safely hold, not the automaker’s recommended pressure, which provides the best balance of braking, handling, gas mileage, and ride comfort. That figure is usually found on a doorjamb sticker, in the glove box, or on the fuel-filler door. If the tire pressure is down 10 psi, our testing has shown that it can make a 1 mpg difference in fuel economy. But far more significant is the impact on handling, braking, and wear – all of which can cost you one way or another.”

Myth #2: You must visit the dealership for vehicle maintenance to maintain your warranty

I grabbed this one off Nationwide’s list of Car Maintenance Myths. It’s a classic fear tactic. What matters is that the maintenance work gets done, as opposed to which certified technician does it. “As long as maintenance is performed on the schedule that’s specified in your owner’s manual, you can take it to any shop,” says Sidney Billingsley, CEO and owner of Woodbridge, Va.-based HomeTowne Auto Repair and Tire. Don’t forget to document all work.

Myth #1: The 3,000-mile oil change

There was a time when the 3,000-mile oil change made sense. Oil quality was inadequate for the demands of the internal combustion engine. With the advent of synthetic motor oil, when AMSOIL came on the scene in 1972 and Mobil 1 a couple years later, new rules came into play. The extended-drain capabilities of synthetic motor oil were well known in oil circles as early as the 1970s. One example is a Society of Automotive Engineers paper by D.B. Barton, J.A. Murphy and K.W. Gardner titled, “Synthesized Lubricants Provide Exceptional Extended Drain Passenger Car Performance,” from November 1978.

In the ’80s as engine technology advanced, automakers began to place higher demands on motor oils. These same automakers were quite aware that motorists found frequent oil changes to be a hassle. For this reason, Mike McMillan of General Motors went on record in 1997 to say, “Extending drain intervals is an important issue for us. We definitely want to be the leader in extended drain intervals.” Though cars in Europe routinely recommend 10,000-mile oil changes, Cadillac was one of the first in this country to recommend 10,000 miles.

Change oil in your car

And yet, even though some owner’s manuals stated in black and white that oil could be changed at intervals of up to 7,500 miles, quick lubes trained their staff to place that “3,000 miles till your next oil change” sticker on peoples’ windshields.

On one occasion I was sitting in a seminar at the annual Automotive Oil Change Association convention in which oil change intervals were being discussed. The speaker was a well-known name in the industry. During a Q&A period after his presentation he was asked about this matter regarding the discrepancy between what he was telling people – to change oil every 3,000 miles – and what their owner’s manuals said. He replied, “Don’t worry, owner’s manuals are like Bibles – the most printed and least read books in the world.” He winked a couple times, and there was laughter. A few people thought this was funny. I didn’t.

Fortunately this has finally begun to be recognized for what it was. If you do a Google search for car maintenance myths, this one regarding oil change intervals is on nearly every list, and usually at the top.

Regardless how often you change your oil – once a year, every six months or according to what your owner’s manual says – we have an oil that delivers excellent wear protection and engine cleanliness to help keep your vehicle running strong.

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  1. Hi Ron,
    Thanks for asking. There were quite a number of factors that made frequent oil changes a legitimate car maintenance procedure. Here are a few of them, each of which can be elaborated on in more detail.

    1. Motor oil was less sophisticated. The 60’s had API SB and SC. It was very early in motor oil development. Motor oil testing and requirements were not very stringent. (Today we are at API SN.)
    2. Motor oils back then were all conventional. AMSOIL, the first synthetic motor oil for automobile use, was still only being developed and would not be introduced till 1972. The motor oils of the 60’s were even lower performing conventional oils than we have today’s oils which are now mostly Group II, and back then were only Group I.
    3. Additives were not nearly as effective or sophisticated as they are today.
    4. The engines had less effective filtration back then, allowing more contaminants and sludge to build up on engine surfaces.
    5. Conventional oil volatility has always been a problem, too. Lighter molecules boil off and the oil thickens. Oil back then would soon fail to be at the viscosity on the label as a result.

    More can be said, but I think you get the picture. Hope this helps.

  2. So, what exactly was the reason for the frequent (i.e., 300 mi) oil changes of the 70’s? At the time I read that the acidic combustion by-products built up in the oil, and could damage metal engine parts, like cylinders. Supposedly the only way to remove these by-products was to drain the oil and replace it with fresh oil.

    Current Amsoil papers admit that both water and acidic components from combustion do slowly contaminate oil. I suppose the basic question is how quickly these by-products build up to a level that could damage the engine? After even a year of driving (maybe 12,000 mi.) are these by-products still at a low enough level to NOT be harmful to the engine? That would seem to be the requirement for such long oil change intervals with synthetic oils to make sense.

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