Regular preventative car maintenance is virtually always cheaper in the long run than episodic repairs. Write that down somewhere, because there will be a test later. The service writer at your dealership or garage should always be advising you about what maintenance is needed (if not, check for yours here), and generally, it’s best practice to follow their suggestions. A well-maintained car will indeed last longer and provide less trouble than one that only sees the inside of a shop when it gets flat-bedded in.
Having said that, there are some unnecessary car maintenance items that can safely be skipped or postponed indefinitely.
Here are the necessary car maintenance items you can feel okay about skipping:
Engine oil is a complex mixture of oils, detergents, surfactants, anti-foam agents, antioxidants, extreme-pressure lubricants, viscosity-index improvers and a dozen other chemicals. You change your oil and filter regularly, right? Then you don’t need to upset this delicately-balanced chemistry by adding third-party additives. Some shops will take advantage of the opportunity to sell you this unnecessary car maintenance item by telling you that your engine will last longer or run better if they add their favorite tiger-milk to your crankcase. I’ve had service advisors do this to vehicles still under warranty, and argue with me about it. At least they did until I pointed out the really fine print in the owner’s manual that says that any additives not specifically recommended by the car manufacturer will void the warranty. Some additive marketers have actually given mechanics a bounty for every additive can cap they turn into the distributor. The only exception I make to this rule is to add a cleaner-style additive immediately before an oil change when I see a car that has a slugging problem cause by neglect.
Ditto for fuel additives, at least as a regular regimen. Everything you need in your gas tank comes out of the pump nozzle. Easy necessary car maintenance you can skip.
Machining the brake discs
Many repair shops automatically “true up” your brake discs whenever they replace the pads. Think old-fashioned LP record that’s warped. Or a Pringle’s potato chip. The disc is supposed to be perfectly flat, and without wobble. Truing it up means machining off the high spots so it is again fit. The high spots will make your brake pedal surge under your foot as you stop.
Shops have to pay for that brake lathe somehow. Removal of some metal from the disc is justified if the disc is out of true or worn from running worn-out pads until the backing plate goes metal-to-metal. But a lot of the time, not so much. If your brake pedal doesn’t pulsate or vibrate, and the brake disc is worn smoothly, truing the discs will only remove metal unnecessarily, hastening the need for eventual replacement. I’ve heard of shops telling customers that their brakes won’t work properly unless the rotors are always machined, which is patently untrue. Don’t fall for this unnecessary maintenance item.
A mechanic only needs to scrape his fingernail across the disc radially once the wheel is off. If the nail catches, the disc should be machined. If not, simply replacing the pads is all that is necessary. This is generally called a “Pad Slap” in the industry. The mechanic can check your discs for true running with a dial indicator as well. If the disc is true to within a few thousandths of an inch, you’re good to go.
Fuel injection cleaning
This procedure is touted as a near-miracle that will improve your fuel economy, drivability, horsepower and probably grow hair. It’s based on a number of half-truths. Yes, if your vehicle has slowly seen degrading fuel economy and power, it may be a result of dirty fuel injectors. To clean them, the shop will hook up an expensive machine that idles your engine on a powerful cleaning solvent instead of gasoline for a half-hour or so. While this will do a fine job of cleaning injectors that are dirty, it will not, as is often claimed, improve power or economy to be better than when the car was new. It can only restore engine operation to its original point.
Dirty injectors are often blamed on cheap gasoline, which isn’t usually true—because most regular gasoline in this country is basically identical between major and off-brands. Surprise, those different brands of gasoline tankers are often filled from the same tanks at the same distribution point. Premium fuel will generally receive an added dose of additives, but that’s added literally as the tanker is filled.
So much for product differentiation. A generation ago, back in the mid-to-late 80s, some vehicles did have regular issues with dirty injectors. The technology has improved, and the EPA has mandated higher concentrations of detergents in gas to keep those injectors clean, rendering this as an unnecessary car maintenance item. Some fuels have even higher levels of additives to keep your injectors clean, and these are classified as Top Tier gas. A few tankfuls of Top Tier gas will get almost any fuel injector as clean as a whistle.
Think this McLaren owner purchased the fancy paint-protection?
Paint Protect/Interior protection
Okay, this scheme isn’t usually peddled out of the service department. It’s the sales department that pitches you as you’re completing the purchase of a new or used car. For only a few hundred dollars, they’ll treat your paint and interior with some sort of miraculous products worthy of a late-night infomercial. Bird poop will slide off. Dog drool and melted ice cream won’t stain your cloth or leather seats. Your car will look like it was freshly detailed forever.
These miracle products are not miracles, in spite of the glossy brochure that shows what your car will look like after just a few months in the sun and acid rain without them. Regular application of a good, over-the-counter car wax, regular vacuuming and an aerosol can of Scotch-Gard will achieve the same end. Don’t worry about getting this expensive unnecessary car maintenance item the next time your car is in the shop.
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Mike Allen is a guest writer for the Openbay blog. He’s an ASE-certified mechanic, longtime former editor of Popular Mechanics, and world-record-holding race-car driver. For more on Mike, check out his bio here, and find him on his own site, Saturday Mechanic.