Top Five Car Maintenance Myths

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were indeed conscientious practices, but over many decades the technology has changed and what was useful long ago is no longer valid.

Here are five that stand 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

“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.”

tailpipe exhaust smoke burning oilMyth #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 sidewall

Inflating tireI don’t know how often you check your tire pressure, but if you’re like most, it’s probably only when the tire looks 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.”

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. Things changed with the advent of synthetic motor oil, which is more robust than conventional oil and capable of lasting longer.

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 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 well-known in the industry. During a Q&A period after his presentation he was asked about 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, the 3,000-mile oil-change myth has be debunked. If you search Google for car-maintenance myths, it’s near the top of nearly every list.

Regardless how often you change your oil, we have an oil that delivers excellent wear protection and engine cleanliness to help keep your vehicle running strong.



  1. I would disagree with the response to the myth that 3k oil drain intervals should be followed. Prior to wide deployment of Gas Direct Injection, fuel dilution and soot was rare in SI engines and extended oil changes was easily achieved. Not the case anymore and manufacturers are plagued with problems due to viscosity shearing and pre-mature wear caused by GDI soot. GM’s second Generation ECOTEC engines with GDI suffer from 2x the wear rate in their engines leading to ring, cylinder, and timing chain wear. The problem is not limited to GM. I have 500 oil samples of non-GDI and GDI engines covering 10 years. GDI fuel dilution and soot is big problem. In my own vehicle I have experienced shearing to a 20 weight oil and increase in wear rate in less than 3k miles using Amsoil Signature Series. Another common Full Synthetic sheared after only 1500 miles. AC Delco SN+ Dexos Gen II only lasted 2500 miles. There our tens of thousands of GM customer that are suffering from pre-mature wear in their engines, sometimes before their warranty is up. Manufacturers and oil additive suppliers are seeking ways to combat this problem. Anyone owner that has a GDI engine, especially high output forced induction engines need to sample their oil multiple times, first at 3k miles before going any longer and then every 2k after that until they know how much fuel diluition and soot is affecting their engines.

  2. 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.

  3. 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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