Most mechanics are decent, hardworking folks. Almost all of them, in fact. That said, more than a few mechanics are known for taking liberties when it comes to diagnosing problems with your vehicle. Some shady mechanics count on the fact that you’re not exactly a car expert. If they think they can get away with it, they will offer you up a load of lie that come with a hefty “repair” bill attached.

A lot of these unsavory repair shops follow the same script. That means victims often report similar stories of inflated bills and unnecessary costs. Many of these unnecessary costs are the same from mechanic to mechanic. So, if your mechanic mentions any of the following red flag items, be sure to get a second opinion. Otherwise you could end up getting ripped off.

The Brake Rotors Need to be Replaced

This is a classic. Remember, just because your brake pads need to be replaced doesn’t mean the brake rotors need replacing too. If it’s the first time your car’s brakes have been serviced, chances are the rotors are fine. The good news is that you can check the rotors yourself.

Take a finger and rub it along the rotor. If the rotor doesn’t have any deep ridges that you can feel with your finger, the mechanic should be able to use a lathe to only scrape off a layer of metal. That will enable you to keep using those rotors, instead of replacing them. This process is called “turning the rotors.” It costs a fraction of what it would to replace the rotors outright.

Changing the Spark Plugs

Another tried and true trick, being told your car needs new spark plugs is as old as the sunset. To be fair, there was a time when changing spark plugs needed to happen at least once a year. That’s because older engines didn’t burn fuel very efficiently, and the spark plugs would become ruined by carbon build up. However, that no longer happens with the engines in today’s modern vehicles.

If a car has fewer than 100,000 miles and your mechanic says it needs new spark plugs, that’s a red flag. Either there’s an underlying problem actually causing it (that they should be able to diagnose), or the mechanic in question is a crook. Either way, it would be in your interest to get a second opinion.

Charging Full Price for Re-manufactured Parts

There’s nothing wrong with re-manufactured or refurbished parts. Just make sure you’re not paying more for them than you should. On an older vehicle, re-manufactured parts are a great way to get a car moving again and save yourself precious dollars. However, many unscrupulous mechanics will charge you for shiny new parts only to fill your vehicle with used ones.

The good news  is that you can look up the cost of re-manufactured vehicle parts online. Websites such as will quickly tell you how much you should be paying for re-manufactured parts versus new parts.

Always ask a mechanic to give you the old parts from your vehicle when you leave their garage. Any autoshop worth going to will happily do this. This way you can inspect the parts yourself. You can also ensure that they don’t end up in the car of another unsuspecting customer. Never trust a mechanic who says he or she doesn’t provide the customer with their old parts. After all, they are your parts. They come from your car. You own them, not the mechanic.

One Fix After Another

Many mechanics will tell you what the problem with your car is, fix it, charge you for the repair, only to find out that — lo and behold — that wasn’t the problem at all! And now your car still isn’t running as it should. The mechanic inspects your car again (and charges you for it). They suggest a new problem with a new repair. (and charges you for that too).

So you begrudgingly pay up a second time. After you leave, your car breaks down yet again. Or that dreaded “check engine” light pops back within 24 hours. What gives? You then turn around, head back to the auto shop, where the mechanic scratches his head in bewilderment. After another inspection (not free), there’s a new problem (huh? how?), and yet another suggested repair (cha-ching!).

Okay, stop the insanity. If you find yourself in this trap, get out of it by heading to another garage. The mechanic in question is clearly ripping you off. You should only ever pay for one repair. If the mechanic doesn’t get it right the first time, you shouldn’t have to pay for him to get it right a second, third, or fourth time.

Not Grouping Repairs When Calculating Labor

There are some parts, like the water pump, that aren’t easy to access on most models. Getting to them requires removing other parts first, just to get access. If some of those other parts are old and worn out too, changing them out at the same time as the water pump makes sense. But what doesn’t make sense is charging customers for the labor on the other parts when it was already part of the water pump replacement.

If the estimate on a repair bill doesn’t exactly line up, or you’re unsure where each labor charge is coming from, that should definitely be a red flag. After all, mechanics should be paid by the hour. Not for each individual part they repair, replace, or, in some cases, simply touch.


Additives are the snake oil of the automotive industry. Many mechanics push additives like they own stock in the companies that make them. Your mechanic might insist that additives are a miracle cure-all for your vehicle. However, the truth is that most additives are unnecessary and a waste of money. Put them in the same pile as the extended warranty.

Additives are not likely to hurt your car. But they’re not going to make it run perfectly either. If there’s a specific issue that your mechanic is trying to fix, like using fuel additive with extra detergents to avoid a more costly cleaning procedure, that’s one thing. If the aim is simply to make the car run better, you should demand an explanation and be ready to say no.

Offering a Free Inspection or Tire Rotation

One of the most reliable ways to get customers (aka suckers) through the door at a garage is by offering a free inspection of your vehicle. Or if you’re lucky, a free tire rotation. The truth is that this is just an excuse for a mechanic to go over your vehicle and recommend as many repairs as possible. Most of which will not be necessary.

The reality is that if there is a problem with your car, you’ll probably know. There are plenty of warning signs that something is wrong with your ride. They are the signal that you should bring your car to a garage for an inspection and repairs. Going to an auto shop simply because a service is being offered for free is a waste of time. It could also end up being a waste of your hard-earned money. Be forewarned.

Replacing the Air Filter

Air filters don’t really need to be replaced that often. When they do, it’s a part that you can quickly and easily replace yourself, for a fraction of the cost that mechanics will charge. Despite this fact, numerous people continue to get duped into paying extra for a needless air filter replacement.

The internet is riddled with stories of mechanics putting mulch or leaves into a car air filter and then showing the customer. “Look how dirty this is!”, they claim as they sell you on a new one. Plus the mark-up on the air filters is ridiculous. Don’t fall for it. Check the air filter yourself periodically. Just Google your make and model to find out how to access it. If you feel it needs to be replaced, head to a local store (or shop online) to buy the filter. Then install it yourself. Again, Google is your friend here for any tentative first-timers. But we promise, it’s really easy.

Fixing the Body Paint

Every vehicle, no matter how nice and expensive, will eventually gets some nicks and scrapes on the body. It’s unavoidable. In most cases, it’s also not very noticeable to anyone but the owner. It also has no impact on the vehicle’s performance or operation.

However, mechanics love to make you feel that your car would look so much better (and somehow run much better) if you just let them touch up the paint a little. Or even better, get your whole car repainted. This is totally unnecessary and a huge waste of money. It won’t even impact the resale value of a car very much, so don’t bother. A tiny nick here and a scratch there is no big deal. Unless there is major damage, there’s no reason to touch the paint job.

Scare Tactics

Most savvy sales people won’t be above using a scare tactic or two to try and pressure you into buying whatever they’re selling. Auto mechanics are as guilty of this as any other salesman. Some of the more popular lines include “I wouldn’t drive a car in that condition,” or “Well if it were my family in the car…”

Some mechanics will even stoop to telling customers that it’s against the law for them to let your vehicle out of their garage unless the “needed” repairs have been completed. Watch out for that one, as it’s an outright lie. They cannot legally detain your vehicle. Call the police, if necessary.

Regardless of what a mechanic says, you should never feel pressure to pay for a repair you are unsure of. This is especially true if you are still able to drive your car at the time. Never hesitate to use a scare tactic of your own. Just tell the mechanic that you’re going to seek a second opinion. Then have the work done at another garage.


This article was worked on by a variety of people from the Autoversed team, including freelancers, editors, and/or other full-time employees.