Car Repair Scams to Watch Out For

Avoid being overcharged for a service you don't really need. Here, the car repairs to drive away from.

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Engine Flush

Engine FlushNiko Guido/Getty Images
Don't let them trip you up: Get an engine flush only if you've been driving the car for several years and notice a buildup of greasy material under the oil cap. If a mechanic says you need a flush because your oil is "dirty," he's lying.

Fuel-Injector Cleaning

Fuel-Injector Cleaning
Fuel injectors should be cleaned, but usually not until they've logged a lot of miles (think 100,000 or more). If the mechanic says the ones on your 20,000-mile car are filthy, he's full of it. However, if you do suspect that there might be a problem with your fuel injectors, play it safe and add fuel-injector cleaner to your gas tank during your next fill-up. Otherwise, if you buy good-quality gas and have a fairly new car, your injectors probably don't require cleaning.

Gas-Saving Devices

Gas-Saving Devices
They do not work. Period. To save gas, accelerate gradually, avoid unnecessary braking, empty your trunk of junk, and learn how to coast effectively.

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Auto-Transmission Flush

Auto-Transmission Flush
Don't even think about it until your odometer has reached 60,000 miles, since most cars have filters that keep transmission fluid flowing freely.

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38 thoughts on “Car Repair Scams to Watch Out For

  1. I teach people how to look for scams and how to work on their own cars!! Just go to youtube and search for: KLOWNY1969 and you can also subscribe to my channel for free to be updated whenever i post a new video!!

    I have something for everybody from the average do it yourselfer to the racer..Come check it out!


  2. Readers Digest.. Perhaps you need an actual automotive expert on your team? You are a little weak in this department. This is the second article I’ve read that skims over important facts or, just flat out recommends against something for the wrong reasons. (Like your ‘don’t buy used tires because if they have been in an accident they are useless’ recommendation on your garage sales article). Let’s get someone else in here writing up your automotive articles. Talk to me.

  3. has anyone here ever seen a dirty fuel injector, fuel injection service cleans carbon build up and allows injectors to inject the correct amount of fuel. Also who writes these articles before putting your trust in their judgement please tell me your credentials

    1. Mike is is right that they over sell it. Infact a lot of gas has additives in it already that are supposed to do this. Also many of them just dump chemicals into the gas to clean them. Sometimes these chemicals can cause the tips to become damaged with the combustion being too hot. When your injectors get dirty it is just best to take them out and clean them. Not run some chemical in your tank.

  4. Just go to autozone get the check engine code read for free and fix whatever is wrong yourself. Mechanics are always going to try to squeeze a little more out of you and may not even do the repair correctly.

    1. Autozone sells parts, period. A code is not a correct diagnosis. Autozone sells more gas caps and oxygen sensors than anyone, when it does not fix your Check Engine light, too bad, your out of that money.

      1. Ted tells the truth as far as it goes. I manage an Auto Zone in California where we are not allowed to pull codes for check engine lights. I feel that there are to many wanna be techs that work in auto parts that will sell you the wrong thing based on what a code says. I personally have owned smog shops so I have a good idea what you would need but it is still a guess without running some checks. Consumers need to understand the difference between pulling a code and performing a diagnosis.

    2. Really JAMIE? Let me ask you, po171 is a lean run bank 1 code. Just what would you replace? Do you have a bad o2? A bad MAF sensor ? A vacuum leak ? A plugged fuel filter or weak fuel pump ? There are many codes that take further diagnostic and people like you seem to think a code reader is a magical instrument that tells you what is wrong when it is a tool that tells you what system is having a problem.

      1. Depends on your code reader and car too. Like mine had exhaust back feeding to the lower O2 sensor. So I new to look under to see my catalytic running red hot. So now I know to change my catalytic and O2 sensor. ( the O2 sensor is the original so about time after 250k miles). Oh and don’t trust the parts guy.
        I had one tell me that a vibrating tensioner is ok. When it means the dampener is bad so it isn’t providing constant tension. That is info right from Cumins themselves.

      2. Good job poorman… Now he’s all types of confused. That’s going to be one heck of a parts bill.

  5. After 20+ years in the industry, and time on both sides of the counter, I quit. I found to many companies ready to rip off the customer at the drop of a hat. With that said, simple care of the machine you drive will make it last a lot longer than the guy’s next door. Read the owners manual, it will give you about the best information on what your car needs. But be aware, that ALL manufacturers are forced to be part of the green movement and their cars and trucks must conform or they can’t be sold in the US. These cars can’t use more than a set amount of disposable stuff like tires and oils. If they do, the company is fined for every car sold. With that said, a 7500 mile oil change maybe should be considered at 5000 or less. Even with the advantage of today’s oils, I change mine much more regularly than the book asks for. But I also keep up with the rest of the fluids and checks similarly. It seems to work, I have 2, ten plus year old cars that are well past 100,000 miles, and of those, one is nearing 200,000 miles. it should roll over the last few hundred about the end of the year. My two pennies, for what it is worth.

    1. I’ve got a 9 year old Suburu Outback with 183,000+ miles and a busted catalytic converter; is there any way to get that replaced cheap? The figure that the dealer quoted me for a new part was outrageous.

      1. If you can get under and cut it off with a high speed drill and a cutting disk or a mini metal cutter like a dremel with a cutting disk, you can do it yourself. The hardest part is if it is welded on and you need to tac weld it in a few places. I have known some guys who would braze it back up. ( wouldn’t advise that unless your good at brazing in a over head position) Some are small enough where exhaust clamps will hold it up too.

  6. This article has some good points. Although not researched very well. Maybe instead of giving false information to unknowing people, do your homework and your job, and not make everybody in the business look like crooks.

  7. I don’t trust anyone to get inside my transmission to adjust anything. I have seen horror stories about what happens after shysters get inside the transmission pan. A flush changes out the burnt non lubricating fluid and in 40 years of working on car I have never seen a clogged filter that didn’t mean the transmission was junk. Also just dropping the pan leaves a lot of filthy fluid in the torque convertor. A flush is the way to go IMO. Also if you do a lot of towing or hard driving the fluid may need to be changed sooner than 60,000. Just pull the dipstick out and smell the fluid. If it smells burnt get it changed. Also if it is anything except a clear red or yellow color change it. Otherwise the info given here is right on the mark.

    1. Real close tiredoldman, but trans fluid property’s are more about it’s ability to absorb heat and save the life of the clutches. But flush is the only way to Go. I’ve seen and used machines that you fill a bladder with 14 qt’s of new fluid, tap in to return line and start car, you can see the darker burnt fluid in a clear tube and when you start fransfer of fluid it’s amazing to see it start to run clear in the end its that good red you want to see. toughs guys that suck some out of dip stick tube are plain ripping you off, but most don’t even know because there only there for payday.Some modern trans don’t even have a dip stick to do this and must return to dealer if you have a problem, witch I do recommend anyway. There are some honest independent shops but they are few and far between, dealers have the proper training and tools for your type of car but service advisers are on commission to so just follow the factory recommendations and you’ll be fine. some say dealer prices are to high but in the end your car will thank you with proper performance.

      1. There has been studies that say you don’t’ get any more additional millage out of a flush or a pan drop. Also a pan drop just makes the filter visible. On older vehicles a pan drop is safer. Also a flush can cause your valves to get clogged up because a lot of your flushes use reverse flow. If you do a pan drop ever 60k miles then your hydraulic fluid ( ATF in most vehicles ) will be in a state that will work perfectly fine for your vehicle. Also you can do the Pan yourself. and spend only 30 to 50 dollars doing it compared to the 100 to 150 for the flush.

  8. Auto transmission flushes are also not recommended by major automobile manufacturers….have a real transmission shop (or the dealer) do a proper transmission service (fluid change, filter change, band adjustment) instead.

    1. Most of the dealers around here try to use a flush instead of a pan and filter. They still try to sell that a full tranny flush gives you the best protection with all the new fluid. I even had a place try to get me to do it with my tranny that has never had one done in over 200k miles. I had to explain to them that the new detergents would create havak in my tranny and that they could losen up buildup and clog the valves in the tranny.

  9. Major automobile manufacturers stopped recommending engine flushes years ago, because the deposits they loosen up often clog other parts of the engine, which can deprive the engine of oil, and ruin it.
    The same people stopped recommending fuel injection cleaning as well, and it’s now considered an ‘improper repair procedure’.
    I’m surprised RD is even recommending these.

  10. Fuel Injectors do not need to be cleaned period. If you have a car that uses regular fuel, every time you get an oil change fill the car up with premium (just once). If you have a car that uses premium fuel, add some seafoam (you can buy it at Napa) every 20,000 miles to the gas tank. You can also add a teaspoon (not a drop more) of ATF to a full tank of gas if the car has higher mileage.

    They are right about the Engine flush as it is a another way to fatten the bill at most repair shops. On the other hand. you should get a radiator flush every 3-4 years (every two years if you live in a hot climate like Arizona).

    For gas saving, check your tire pressure periodically and make sure that they meet the manufacture’s specifications. Changing your oil at the correct intervals or even using full synthetic oil can help increase your gas mileage. Also I would advise checking some of the car forums about your car’s “sweet spot” as there is usually a speed (ex. 55, 60, 63 MPH) that the car performs the most efficiently.

    I went to school for mechanics and they go over this repeatedly.

      1. To clarify what I previously wrote, a customer should never pay to clean their fuel injectors. If you read what I wrote, you can clearly see that my intention was to help out others…

        1. Clearly, your intention was good. :-)
          You still contradict yourself though because you are still paying to clean your injectors although not via having to pay someone to professionally do it for you, it is done through chemicals you add yourself. Six of one -half dozen of another. A lot depends on how well the engine has been maintained as to whether the fuel injectors can get clogged.

          Personally I use BG-44K and know a bunch of mechanics that will vouch for its effectiveness.

          1. Also it doesn’t matter if you use premium fuel or 87 octane. Most cars cannot combust premium as well as the lower octane. I have heard teachers in school give bad advise as well. They are still debating in mine over using a little of Tranny fluid in the fluid to clean injectors. Oh it does work but if can melt the tips right off. Especially in Cummings diesel engines.

          2. Most cars? What octane they burn best depends on what they’re designed by the factory to burn the most efficient. A car designed to run on 85 octane will still run on 91 although it’s a waste of money whereas a car designed to run on 91 will still run on 85 although there will be a reduction in power output.

          3. Most cars, some dude, are designed for 87 octane. Those engines normally do not produce enough compression to combust the 91 octane efficiently. Now if your car is running rough or pinging the higher octane can be used to smooth things out.

        2. You were right on that. Sometimes the best way to clean them is to just take them out and brass brush them clean. It is something I do in large trucks and smaller vehicles all the time when inspecting injection issues. You be surprised what cleaning a tip and replacing the o-ring (if one is on it ) can do. it also makes it so you can see if there is any micro cracks.

        3. Oh Cory learn more about fuel systems. Most techs don’t have a clue about them. You can make tons of money for just being able to quickly diagnose fuel problems.

      1. Hmmm, I do see you have a calculated argument against him… Or did I miss it?

    1. Cory you have to be careful with the ATF fluid. It combusts at a much higher temp than your gas and can melt injector tips. Also the teaspoon amount doesn’t have enough to clean the injector tips. Most Old timers would recommend 1/4 of a cup when you fill your tank but that is a risk to some problems. The newer cars you have to be even more careful and if your running a diesel i wouldn’t put any additives in that car at all. Especially if it runs off a CR injection. ( additives can let water get past the separator and explode the injector tip and ATF in that can definitely melt the tips with the higher temps and compression in diesel)

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