Even the smallest repair on your car can cost a whole lot of cash. Mechanics are businessmen. As a service-oriented job, they need to get as much money out of you as possible. So, the less you know, the more easily they can overcharge you.

It helps to know the basics of a car, and how to fix some common problems. For example, if you even knew how to change your car's oil or rotate the tires, you can cut the servicing bill substantially. Like with everything else, the internet is here to help.

1. How a Car Works (Web): A Dummy's Guide to Understanding Cars

Unless you went to engineering school, you were never taught how exactly a car works. When you hear someone say, "Oh, it's the carburetor," you should know what they're talking about. How A Car Works is an illustrated, detailed guide to teach you every part of a car.

Car Repair Apps -- How a Car Works

What sets the site apart from other online explainers like HowStuffWorks are the illustrations. Clearly labelled and with simple explanations, you will soon know everything there is to know about cars. But the best part is the quick-look car dictionary. Whenever the site uses a technical term, you can hover your mouse over it to see what it means. It's the difference between a decent guide and a great one.

How A Car Works is also available as a gorgeous PDF ebook, for a price of five dollars. If you're serious about learning cars, it's totally worth every penny. But otherwise, stick with the free website and learn what you need to.

2. Dash (Android, iOS): Hack Into a Car's Diagnostics Center

Here's the dirty little secret no mechanic is going to tell you. If the "Check Engine" light is on, they'll whip out a fancy specialized gadget to diagnose the issue. It'll cost you a pretty penny. But you don't need to pay an exorbitant amount to find out your car's problems. A $10 gizmo and your smartphone is literally all you need.

Every car has a built-in smart diagnostics center called OBD-II or OBD2. OBD stands for On-Board Diagnostics. This is what activates the "Check Engine" light if something is wrong. OBD2 has been the worldwide standard for over a decade, and has a standard port in all cars, somewhere near the steering wheel.

You'll find scores of $10 OBD2 Bluetooth connectors on Amazon. Plug it into the OBD2 port, pair it with your smartphone, and start Dash.

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Dash will unlock an incredible amount of information about your car, which you didn't know was hiding all this while. It will tell you exactly what the check engine light's error code means. It also brings up historical data about your car's usage so far. Dash can also work as a Bluetooth-based finder, in case you forgot where you parked.

The more you use the app, the more reasons you'll find to fall in love with it. Dash is simply brilliant, and any car owner should spend the $10 on an OBD2 Bluetooth adapter right away.

Download -- Dash for Android [No Longer Available]  (Free) or for iOS (Free)

3. Car Problem Zoo (Web): Is the Problem Simple or Rare?

So, your car has some steering trouble. It happens. But your mechanic is going to make it sound like it's a rare problem that needs some expert tools and parts. But what if the car model is known to have this problem? Then a solution would be easier to find. That's where Car Problem Zoo comes in.

Car Repair Apps -- Car Problem Zoo

Car Problem Zoo is a repository of all the complaints files by car owners in USA with the U.S. Department of Transportation. It sorts this data by car manufacturers, the year of release, and common car problems. With your car's model and year of manufacture, you'll be able to pinpoint whether your problem is prevalent or not. The full complaints are available to read on CPZ. You might want to check the recalls section and the bulletins as well.

4. Eric the Car Guy (Web/YouTube): Car F.A.Q.s and Videos

Before you go to a mechanic, check up with Eric the Car Guy. He knows everything there is to know about cars. He is also excellent at making YouTube videos explaining what he knows, and has put together one of the best car F.A.Q. pages on the internet.

On YouTube, Eric is a natural in front of the camera. His easy-going attitude and calm explanations will make you realize it's just a car, and it can be fixed with a little knowledge. From motor basics to DIY solutions, this is the place for those who like to see and listen instead of reading.

Eric's F.A.Q. page is neatly sorted for anyone to troubleshoot their car problems. Select the issue from categories like no start, engine overheat, transmissions, vibrations, etc. You'll then get every possible variation of that issue, and every possible solution. It's a rich database of questions and answers to solve common car troubles.

5. Carjunky Forum (Web): Discuss Repairs and Get Advice

When technology and databases don't help, you need to turn to human brains for advice. Carjunky's forum is a hub for the internet's gearheads, and you'll always get some help here.

Car Repair Apps -- Carjunky

Don't just click the link and start blabbing about your problem. Take a breath. Now, first search the forums to see if someone has already addressed your problem. It's the zeroth rule of all forums, and trespasser's requests for help are ignored. Plus, it's nice to get an answer without having to ask a question, right?

In case your problem is unique, register for an account and post it. But before you do, read the guidelines and rules thoroughly. There's a particular format and way to do things. If you follow the rules, you'll get help from knowledge folks. Break the rules and it'll get ignored, deleted by moderators, or you'll find motormouths among the motorheads.

If you can't don't want to bother with all this formality, you'd be better off using Reddit productively at /r/CarTalk. For DIY auto repairs and fixes, it's the perfect place for newbies.

Tell Us Your Mechanic Horror Story

Hopefully, these tools should help you avoid being overcharged by an auto repair shop. But come on, everyone has had one terrible experience getting ripped off by a mechanic.

Tell us your horror story in the comments below.

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