DIY - Diagnose Your Car Without Specialty Tools

DIY - Diagnose Your Car Without Specialty Tools
Posted in: How To and Tips

Shhh. Your Car is Talking to You. Do You Know How To Listen?

There are a lot of fancy diagnostic tools for cars and trucks that can tell you what’s wrong in an instant. But these specialty tools are not always affordable and some work best with training. If this isn’t quite in your budget or you want to do things the DIY way, this is the blog for you. Learn how to diagnose your car problems without specialty tools.

1. Changing Out Parts

Your car has multiple parts that come in pairs from headlights and ignition coils to wheel sensors, spark plugs, plug wires, and more. If you believe one of these parts is malfunctioning, you can easily test it by switching with one that should be good. If the new part works, replacing it should fix the problem. If it doesn’t, it likely means that the issue is deeper.

If your turn signal bulb appears to be bad swap it with the working turn signal bulb or a working reverse light bulb. If the new bulb works, the issue was the old bulb. Throw the bad bulb away and buy a replacement. You can do this with car speakers, window switches, car fuses and relays, and much more. Just make sure that the parts you are swapping for this diagnostic are compatible and identical. Check size, shape, connections, and if there’s writing that discusses voltage or loads compare the numbers.

When replacing the part that’s not working with a good part, but the new part doesn’t work either, it means the issue is deeper than the surface parts. If the part you’re testing doesn’t have duplicate parts on your car to pull from, you may have to buy the parts you need to test it.

2. Condition of the Auto Parts

It’s not difficult to diagnose some issues on a car if you just know what to look for. Check for bad connections on wires and connectors. Look for burn marks at electrical connections or melted plastic connections. Look for parts that are worn, corroded, or crumbling. These are all great things to look for when your car isn’t performing as it should.

When checking your engine for potentially faulty parts, you want to pay close attention to the working order and physical appearance of the items. Are they deteriorating, worn out, cracked, burned, or discolored from excessive heat? Do they wiggle or seem loose?

Do you hear strange sounds coming from your car? If so, we have to find out where they are coming from. Paying attention to when they happen can be very useful in determining where the noise is coming from. Does it happen when you turn the wheel, step on the gas, hit the brake, go over a bump? Once you notice when it happens and can recreate it, then you know where to start.

*DIY Mechanic’s Note*: Always let a hot engine cool before sticking your hands down in there and never remove the radiator when a car is hot.

3. How Do Your Fluid Levels Look?

You should check your fluid levels regularly. This includes engine oil, coolant, transmission fluid, power steering fluid, and brake fluid. Being low on any of these come with risks of car damage and passenger safety. If you are low on engine oil your engine can overheat and seize from the friction. Before the engine gets that bad, you may hear a ticking sound when you drive that is much louder when you accelerate. That ticking noise is likely your lifters. If adding oil fixes the ticking, that was likely the issue but why was your oil low to begin with? Check for leaks or oil-burning smells.

Being low on coolant means you will not have heat in your vehicle and your engine could be at risk of overheating. This can cause major engine damage. Transmission fluid makes sure your transmission shifts correctly and lubricates the gears to prevent damage from friction. Power steering fluid keeps your power steering working. Without it, it may be nearly impossible to turn your vehicle. If you notice a whining or grinding sound when turning, you may be low on power steering fluid.

*DIY Mechanic’s Note*: Being low on any fluid is usually caused by a greater issue like a leak or your vehicle is burning it for some reason. So definitely put more fluid in to prevent damage but make sure you look for leaks or burning smells so you can fix the problem and not just the symptoms.

4. A Dead Battery?

You go to start your car and get nothing or maybe just some low-ticking noises. Your battery is likely dead. But what causes a dead battery? 9 times out of 10, it’s a user error. Leaving the headlights on or letting it sit for months without driving are a couple of common reasons the battery could be dead.

When the key is in the on position, do you have cabin lights? Are your headlights on? Are all the lights on but dim? If they are dim, it’s probably the battery. If lights are all bright, the issue could be in the starter system.

Check to make sure your battery connections are clean and free of corrosion. Many local auto parts stores will test a battery to make sure it’s still good and can hold a charge for free.

*DIY Mechanic’s Note*: Your alternator is what runs your car after you start it. It also charges the battery. The most draining thing your battery does is starting your car. If you only drive your car short distances; To school, the grocery store, the pharmacy, etc. you are not giving your battery enough time to recharge when you drive. This can seriously shorten the life of your battery. You must occasionally put more miles on that battery in one trip to charge it and prolong its life.

5. Car Vibrating and Shaking?

If your car is vibrating and/or shaking as you’re driving down the road, it’s impossible to ignore nor should you ignore it. Let’s look at some ways that we can diagnose why the car or truck has a shimmy, a shake, or a wobble.

Have you noticed that your car’s vibration doesn’t happen at lower speeds but rather after you hit 50/MPH? This is typical of a driveline vibration and could be from the center support bearing, u-joints, or bad bushings. Rotate the u-joints while shaking them to see if they have any play in them. If they move side to side while shaking them, they will need to be replaced.

Does your ride seem extra bouncy when going down the road? If so you need to test your car’s suspension with a bounce test. Attempt to bounce the car to see when it stops bouncing. Once you stop bouncing the car it shouldn’t bounce more than one to two more times. If it continues to bounce beyond that you need to replace your shocks or struts.

*DIY Mechanic’s Note*: Always conduct the bounce test from all four corners separately. This will help you to determine which corner or corners are bad. It’s best to replace shocks in matching pairs. If you have to replace the left front shock, also replace the right front. They do begin to leak and sag over time.

Check your wheels to make sure your lug nuts are tight. Raise your vehicle and try to wiggle or shake the tires side-to-side. You are looking for excessive play and noises in the tire and suspension assembly. Bad tie rods, wheel bearings, and lower ball joints are some of the things that could cause this vibration


Diagnosing your car without the special tools like a BLUETOOTH OBDII scanner can be a lengthy process but with time, patience, and practice you will find that your instinct is one heck of a car diagnostic tool. Whether you want those specialty tools or you are diagnosing your car the old-fashioned way, PartsHawk.com has what you need to get your back on the road quickly at a good price. Contact us with questions or for help finding the right part.

3 months ago
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