top mechanic diagnostic tools for your car

Pixabay.com / CC0 1.0.

Top 11 Mechanic and Diagnostic Tools for Your Car

If you have the right tools and equipment, you can perform many minor automotive repairs and routine maintenance tasks at home. Working on your car can save you time and money, and solving a problem on your own can be quite rewarding. Before you invest in a complete set of tools, it’s helpful to know which tools are most important, how much they cost and when to use them.

1. Full Set of Screwdrivers

Image courtesy of Pixabay.com, licensed under CC0 1.0.

Pixabay.com / CC0 1.0.

A full set of screwdrivers is one of the most versatile toolsets that you can have. You can muddle through many situations with just a basic medium-sized flathead and medium-sized Phillips screwdrivers, but the basics won’t cut it for the full range of screws used in cars. A full set will allow you to easily operate all of the screws in your car without stripping their heads.

Cost: You can expect to pay between $10 and $150.

When to Use It: Whenever you need to screw or unscrew something.

When Not to Use It: Don’t use your screwdrivers as pry bars, chisels or wedges. Screwdrivers aren’t designed for these uses and may break or slip when used in unorthodox ways.

2. Pliers

Photo by Typhoon at English Wikipedia / CC BY-SA 3.0 / GNU FDL 1.2

Photo by Typhoon at English Wikipedia / CC BY-SA 3.0 / GNU FDL 1.2

A set of pliers will allow you to cut wires, adjust bolts, grip objects in tight spaces and more. There are many different types of pliers, and many of them offer great utility for auto repairs. Try to find a set that includes a pair of angled needle nose pliers to grip objects that don’t allow direct access.

Cost: A set of pliers will cost between $20 and $80.

When to Use It: Pliers are excellent tools for gripping objects or cutting wires, and they are especially useful for gripping items in tight spaces.

When Not to Use It: Don’t use pliers as a substitute for a screwdriver or a ratchet. Never cut wires with a plier unless you’re certain that there’s no power flowing through the wire. Delicate objects can be inadvertently crushed if you try to grip them with pliers.

3. Ratchet Sets

best diagnostic tools for car

Photo by KMo Foto on Flickr / CC BY 2.0.

Ratchets allow you to easily tighten or loosen bolts. Most ratchet sets include a variety of different ratchet heads to fit different bolts snugly. Depending on your vehicle, you may need either a metric set or an SAE set to fit the bolts used in your vehicle. Some sets may also include items such as bent handle ratchets, ratchet extenders or flex ratchets to allow you to operate bolts that are otherwise inaccessible. Finger ratchets can help you access bolts in particularly tight locations.

Cost: Ratchet sets vary widely in cost, but a quality set can cost up to $100.

When to Use It: Whenever you need to operate a bolt and you have the space to operate a ratchet.

When Not to Use It: Don’t use a ratchet if you can’t get a snug fit on the bolt. If the bolt is on too tight, you may need to use a different tool; attempting to loosen a too-tight bolt with a ratchet can break your tool.

4. Wrenches

Photo by Kyle May on Flickr / CC BY 2.0.

Photo by Kyle May on Flickr / CC BY 2.0

Wrenches fill many of the same roles as ratchets, but these tools are a little more versatile. They’re often smaller and thinner than ratchets, so they can fit in tight spaces easier. In addition, the longer handles on wrenches allow you to exert more force on a stubborn bolt. Wrenches are often used to hold bolts in place while a ratchet loosens the bolt. Metric wrench sets are often needed for imports, and SAE sets are needed for domestic vehicles; if you’re uncertain which you need, ask your dealer.

Two other types of wrenches are commonly used in auto maintenance. Strap wrenches feature an adjustable strap attached to a rigid handle; these are often used on oil filters and other smooth surfaces. Torque wrenches include a torque meter on the handle, allowing you to tighten bolts to the proper level to ensure the optimum fit.

Cost: A regular set of wrenches will cost between $30 and $120. Strap wrenches usually cost between $10 and $20 each, and a quality torque wrench will cost between $50 and $100.

When to Use It: Whenever you need to tighten bolts but can’t use a ratchet. Torque wrenches should be used whenever a bolt requires a precise torque level.

When Not to Use It: If you can use a ratchet, it’s often better to use the ratchet over a wrench. Don’t use a torque wrench for most of the tightening; instead, only use the torque wrench to finish the final tightening.

5. Allen Wrenches

Image courtesy of Andrew Gustar on Flickr, licensed under CC BY-ND 2.0.

Photo by Andrew Gustar on Flickr / CC BY-ND 2.0

Allen wrenches are simple L-shaped tools for fastening and unfastening a variety of fasteners. Each individual hex wrench is sized to fit a particular bolt head; unlike traditional wrenches, which attach to the outside of the bolt, Allen wrenches fit inside of a hex-shaped pattern on the inside of the bolt head. These wrenches come in both SAE and metric sizes, but most sets of Allen wrenches include both types of sizes.

Cost: A complete set usually costs about $20.

When to Use It: When tightening hex bolts.

When Not to Use It: Any other time.

6. Jack with Stands

Image courtesy of Ryan Frost on Flickr, licensed under CC BY 2.0.

Photo by Ryan Frost on Flickr / CC BY 2.0

If you’re doing any work on your tires, wheels or the underside of your car, you’ll need a jack to lift your car off the ground. Once you have your car lifted to the desired height, you’ll also want a set of sturdy stands to hold your car in place; jacks can and do fail, and you don’t want your jack to fail while you’re underneath your car.

Cost: Expect to pay anywhere from $250 to $1,000 for a quality set of jacks and stands.

When to Use It: Whenever you’re working under your car.

When Not to Use It: Try to only use this tool on level ground.

7. OBD-II Code Reader

A code reader is an invaluable tool when diagnosing problems with your car. OBD stands for on-board diagnostics, and most cars now use the second-generation tools, as denoted by OBD-II. When something is wrong with your car, the sensors in your car will output a fault code. When you attach a code reader to your vehicle, you can read which fault codes are currently active in your engine; there are more than 3,000 generic and model-specific fault codes used, so you may need to use an online tool to look up the exact meaning of an individual code.

Cost: Basic models start at around $60, but full-featured models will cost a few hundred dollars.

When to Use It: Whenever your “Check Engine” light is illuminated

When Not to Use It: There’s never really a bad time to use this tool, but don’t take it too literally. Engines are complicated machines, and multiple fault codes can be triggered by simple problems.

8. Multimeter

Image courtesy of Pixabay.com, licensed under CC0 1.0.

Pixabay.com / CC0 1.0.

Multimeters are helpful tools for diagnosing electrical problems. To use a multimeter, use the probes to test a circuit that you suspect is faulty. This is especially useful for diagnosing problems with engine sensors, which can erroneously send fault codes if their electrical components fail.

Cost: Multimeters range from $10-$80.

When to Use It: Whenever you suspect that an electrical component may not be functioning properly.

When Not to Use It: There aren’t really any bad times to use a multimeter, but always follow your meter’s instructions to avoid damage to the unit or yourself.

9. Vacuum Pump, Bleeder and Pressure Testing Kit

Many parts of your engine rely on vacuum pressures to work, especially your cylinders. These tools can help you test vacuum lines if you suspect that one of your lines is leaking. To test for a leak, simply spray a little bit of carb cleaner on potential leaks and connect your vacuum pump to the line. If there is a leak, the gauge on your testing kit will flutter. You can also use these tools to bleed your brakes.

Cost: You can get a kit starting at $20, but more comprehensive kits will come in between $50 and $100.

When to Use It: Whenever you suspect that one of your vacuum lines may be leaking. You can also take periodic vacuum readings to monitor the overall health of your engine.

When Not to Use It: When you car’s engine is cold, your vacuum readings won’t be accurate. Make sure the engine is at operating temperature before taking readings.

10. Fuel Pressure Gauge

If your car has been acting underpowered, a fuel pressure gauge can help you determine if the fault lies with your fuel system. After connecting your gauge to your fuel system, you can monitor your system for proper pressure. Before using one of these devices, however, you’ll want to research the proper steps for your particular vehicle.

Cost: You can expect to pay between $20 and $250 for one of these tools.

When to Use It: Use this tool if your car has been acting sluggish; it will help you diagnose problems with your fuel system.

When Not to Use It: Always follow the instructions for your vehicle when using a fuel pressure gauge, and make sure to clean up thoroughly afterwards. Failure to do so can cause an engine fire later on.

11. Circuit Testing Light

By allowing you to quickly eliminate possible wiring faults, circuit testing lights make diagnosing electrical problems easier. After grounding one end of the light, you can simply probe any spot along a circuit that should be receiving power. If the light illuminates, then you know that you have a good connection.

Cost: Between $5 and $20.

When to Use It: Use this tool to quickly eliminate potential sources of an electrical problem.

When Not to Use It: This tool is useful for establishing that an electrical circuit exists, but it won’t tell you anything about the actual details of that circuit. Always use proper safety procedures when working with electricity.


Do you already own any of these tools, and have you ever used one for an at-home repair?

Which tool do you think is most useful? 

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