These Are the Cheapest Things (To Fix) That May Go Wrong on Your Car

Be it your humble Camry or a five-valve-per-cylinder F355, negligence is the number one reason for the poor condition of so many vehicles on the road today. Also consider the monetary aspect, with some dealers charging way too much for a simple oil and filter change for both the parts you purchase and the labor. DIYing is the best way of saving a few bucks here and there, for the replacement parts can be procured at lower prices via insert big-name retailer here. You also won't have to pay for labor, although you won't do said oil and filter change as fast as a dealer technician can.

It's no secret that we live in a day and age where you can become an informed car owner even if you are not mechanically inclined, so do not be that scared of maintenance and small-time repairs that you can do yourself. An independent mechanic that you can fully trust and won't rip you off on parts is a great solution for those who simply don't have a knack, the tools, or the time for DIYing, albeit such mechanics are hard to find nowadays.

The following listicle comprises the kind of things that can ruin your automobile or how you perceive your automobile if not looked after, with said things being objectively affordable to replace or fix. Some of the following operations can be performed in your garage or driveway with common tools, while others require specialized tools or techniques. On that note, let's kick this off with the vascular system of any combustion vehicle.

Engine oil and oil filter

If the engine control unit and other control units are considered the nervous system, then engine oil is the vehicle's lifeblood. Engine oils come in many flavors, with most new cars, utility vehicles, and trucks running full synthetic for improved fuel economy, cleaning properties, better viscosity at low and high temperatures, and turbocharger protection.

First and foremost, you need the right oil in the proper amount, along with the right oil filter. The owner's manual lists everything. In the 2024 Ford Mustang GT's case, page number 371 reads 10 quarts or 9.5 liters of Motorcraft SAE 5W-30 or 0W-30 in cold weather. On page 368, the oil filter is listed as FL-500-S.

In order to change oil, you will have to lift the car using ramps or jack stands. The golden rule is never work under a vehicle held up by a lone floor jack, for that can go badly wrong. Most vehicles feature an undertray that needs to be removed in order to access the oil pan and filter. Be that as it may, the GR Supra's oil filter is located in the engine compartment.

Following the removal of the undertray, locate the drain plug and loosen it counterclockwise. Make sure your used oil container is properly situated. After something like five minutes, remove the filter with utmost attention to the rubber O-ring. This part should be removed so that the new O-ring can properly seal the filter in place. This further applies to the drain plug washer as well, but you'll need to check your owner's manual to see whether said washer needs replacing with every change.

Before installing the new filter, do apply a coating of engine oil around the rubber gasket. After the new filter and plug, you have to reinstall the undertray before starting to pour oil. It's recommended to use a funnel because it may get messy otherwise. Always fill to the oil volume indicated in the owner's manual for your specific engine. For reference, the 2.3-liter EcoBoost four-cylinder 2024 Mustang takes 6.0 quarts (5.7 liters) as opposed to 10.0 (9.5) for the Coyote-powered Mustang GT.

Refasten the oil cap, lower the vehicle back onto the ground, then start up to allow the oil to circulate. The final step is to ensure that your engine oil level is between the L and F marks of the dipstick. If you're an extra careful type, also check for leaks around the oil filter and on the ground. GR Supra doesn't have a dipstick, but does have a sensor that measures the oil level. Furthermore, many vehicles also require you to reset the oil change reminder.

As of this writing, a 1-quart bottle of Motorcraft SAE 5W-30 retails at less than $7 on Ford's parts website. As for the oil filter, make that around $9 for the Motorcraft FL-500-S of the S650 Mustang GT. Provided that you already have the ramps/jack stands and tools required for an oil change, DIYing would set you back 80-odd dollars. Excluding the shipping costs, of course. Alternatively, the folks at Late Model Restoration charge $74.99 on a Mustang 5.0 Motorcraft oil change kit, with free shipping for orders over 99 bucks.

Air and cabin filter

In keeping with the automotive and human body analogies, the air filter is your vehicle's lung. Having already mentioned the S650-generation Mustang GT, we also need to highlight that some cars feature two air filters. In a similar fashion to your lungs, the air filter is designed to keep out bad stuff from getting into the internal combustion engine, preventing damage to the cylinder walls, piston rings, and other expensive parts.

Once again, the owner's manual is where you'll find the part number of the original equipment air filter. There are plenty of alternatives out there, but always make sure that they're compatible with your vehicle. What's more, buy well-known brands such as Bosch, K&N, FRAM, and so forth. Both in terms of tools and effort, the air filter is much easier to replace than the oil filter. Simply follow the duct from the intake to the large plastic housing where the filter is located, release a few clips, remove the old filter while preventing the yucky stuff from falling off of it, and install the new filter in the correct orientation to the airflow.

Every engine air filter change should also be accompanied by a cabin air filter change. This one is often located behind or underneath the glove box. The owner's manual should have all the information on glove box removal to access the cabin air filter. Bear in mind that certain vehicles have it in the engine compartment. Similar to the engine air filter, the brand-new cabin air filter should be installed in the proper orientation. The arrow on the side of the filter is your friend.

Brake pads and rotors

If you thought an oil change is hard, a brake job is harder still. It's extremely important that brakes on their own don't mean a thing if your tires are worn, old, or both. To this effect, keep a close eye on your tires and regularly check the air pressure – ideally once every month – for optimum performance. That said, brake pads wear quite a bit faster than rotors. The front pads wear faster than the rears because they handle more weight under braking.

If the job is too big for you, it's no shame to have the mechanic or dealer of your choice to replace the brakes. After all, getting a brake job wrong can have catastrophic consequences. The easiest way to identify the correct brake pads and rotors for your vehicle is to run the model year, make, model, and engine on a well-known retailer's website.

After lifting the vehicle and removing the first of four tires, remove the caliper slide pin bolts, then hang the caliper by a coat hanger to keep it out of the way. It goes without saying that you should never let calipers hang on their caliper hoses. A brake piston compressor is needed to compress the caliper piston. After that, remove the caliper bracket bolt and the bracket for the rotor to slide off the hub. A few hammer taps will loosen up any rotor.

Slide the brand-new rotor in and fasten a lug nut to hold it in place while sliding the caliper bracket back over the rotor. Fasten the bolts to the recommended torque specifications, then install the new hardware in the caliper bracket before sliding the new pads in. But first, lubricate the brake pad ears with brake lubricant to avoid excessive friction on the pad's backplate. Cleaning and lubing up the caliper bracket slide pins is the next step, then fasten the pins to the correct torque specs.

Repeat for the other three wheels, reinstall the wheels, lower the vehicle onto the ground, and you're done. Or not because you have to check the brake fluid level. Top it off to the maximum fill line, refasten the brake fluid reservoir cap, then slowly pump the brake pedal until it feels nice and firm. Do not press it all the way to the floor because the master cylinder won't like it. Now check the brake fluid level again. If necessary, top off again.

It's wise to do a road test after every brake job to ensure that the new components are installed correctly and work as intended. As for changing the brake fluid, you're better off leaving that to a certified technician because it's easy to get the bleeding process wrong. The brake fluid change interval depends on the type of brake fluid. DOT 3, 4, and 5.1 are hygroscopic brake fluids, meaning that you'll have to change them every two years or so due to their property to absorb water/moisture.

Coolant

Similar to an oil change, flushing your coolant requires you to have the vehicle on a level surface. Let the vehicle sit for an hour or so for the engine, radiator, and coolant to cool off. Open the radiator fill cap, and – if your vehicle has one – the cap of the extra coolant reservoir. The drain plug of the radiator should be at the bottom of the radiator. Place a pan under it, then loosen the plug to allow the coolant to flow. Retighten once it's all out of the system.

Now fill the cooling system with distilled water. A radiator flush product is highly recommended to clear sediments and corrosion. Reinstall the cap(s) and run the engine for 10 minutes with the heater on full blast, let the vehicle sit for half an hour, then repeat the drain procedure. As for the refilling process, you can either buy pre-diluted coolant or coolant that needs to be mixed with distilled water. The ideal mixture is 50 and 50 percent. After pouring in the right amount of coolant, start up the vehicle with the radiator cap off to bleed air bubbles from the system. Top up if necessary. When the coolant level begins to rise, that's your cue to refasten the cap.

Ford lists no fewer than five coolant capacities for the seventh-generation Mustang. They range from 10.46 quarts (9.9 liters) for the base EcoBoost to 12.8 quarts (12.1 liters) for auto-equipped performance versions of the naturally aspirated V8. The manual, on the other hand, takes 11.7 quarts (11.1 liters) of Motorcraft Yellow Prediluted Antifreeze coolant (part number WSS-M97B57-A2).

Spark plugs

Gassers need spark plugs in order to ignite the oh-so-important air/fuel mixture, thus resulting in controlled explosions. These explosions give linear motion to the pistons while the crankshaft converts the linear motion into rotational motion. Pretty sweet, huh? Regardless of your injection system, the spark plugs are relatively easy to replace. The operation should be done with the engine cold and the battery terminals disconnected. Older vehicles feature spark-plug wires connected to the ignition system, whereas newer vehicles flaunt coil-on-plug units. In other words, an ignition coil for each individual spark plug.

Spark-plug wires can be removed by pulling them out while holding on to the boot that slips over the plug. Do label each and every wire because internal combustion engines have a thing called firing order. When it comes to coil-on-plug connectors, gently depress the locking tab with a flat-head screwdriver in order to pull each and every one of them out. A spark-plug socket is needed to remove spark plugs. Fit it over the plug, then gently unscrew counterclockwise. As the old saying goes, left loosey, righty tighty. Don't allow any debris to enter the spark-plug hole. Inspect every new spark plug for cleanliness, straightness, and no cracking or chipping. Some spark plugs are pre-gapped, while others have to be gapped.

Simply use the correct feeler gauge between the center and side electrodes, then adjust the gap accordingly. The owner's and/or service manual is where you'll find the correct gap. On the S650 Mustang GT, the numbers are 0.049 to 0.053 inches or 1.25 to 1.35 millimeters. Now thread the new spark plugs into their cavities without cross-threading or forcing the plug in with excessive force. Anti-seize lubricant on the threads will ensure that your spark plugs will come out easily on the next change. Finally, reattach the wires or connectors in the correct order, reconnect the 12-volt battery, and that's a job well done.

Transmission fluid

Although transmission fluid isn't changed as often as engine oil, you should change it at the recommended intervals. Old transmission fluid does not lubricate metal-to-metal touch points as well as fresh transmission fluid, nor does it keep the transmission sufficiently cool during spirited driving or while towing.

Automatic transmission fluid is a different breed from what manuals take, so be careful with what you're buying. As ever, read the owner's manual before placing an order. On a manual, first jack your vehicle up, locate the filler bolt, and loosen it without removing it completely. Then locate and remove the drain bolt to allow the fluid to drain. Instead of sitting idly, clean the magnetic inside portion of the drain bolt of metal shavings. Now you can remove the filler bolt. Before adding gear oil into the gearbox, retighten the drain bolt to the correct torque using a torque wrench.

Once the transmission fluid starts oozing out of the filler, it's time to retighten the filler bolt. Due to their designs, certain automatic transmissions require you to loosen the pan bolts to remove the pan. If so, replace the transmission pan gasket as well. Only after reinstalling the pan and securing the bolts can you start adding fresh automatic transmission fluid through the dipstick hole. Leave a bit of fluid in your last bottle because you'll have to check the fluid level after shifting through all gears on a short drive. Check the level on the dipstick after the drive, and – if needed – add some more automatic transmission fluid.

Serpentine belt

Internal combustion vehicles feature either timing chains or belts, and the latter should not be confused with the serpentine belt. As opposed to the timing belt, which keeps the cam(s) and crankshaft in perfect sync, the serpentine belt drives the water pump, alternator, A/C compressor, and steering pump. Indeed, it's a very important belt.

Step one is checking the tensioner arm for excessive movement, and replace if necessary. You can also use a serpentine belt tool to check for smooth rotation. Also inspect the pulley/roller. If it shows a rough surface or does not spin smoothly, replace it as well. To rotate the tensioner in order to remove the old serpentine belt, use either a serpentine belt tool or a socket with a breaker bar or a long ratchet on the tensioner pulley's center bolt.

Rotate the tensioner, slide the belt off the pulleys, then smoothly release the tensioner before removing the old serpentine belt. Now route the new belt around the correct path. You have to rotate the tensioner while loading the belt around it. Now wrap the brand-new belt around the crankshaft pulley, followed by the other pulleys. After sliding the belt on the final roller, simply release the tensioner and make sure that the serpentine belt is perfectly aligned with all pulleys and follows the correct path.

12-volt battery

With all the different kinds of 12-volt batteries available today, one would think that choosing the right one is pretty difficult. In truth, it most certainly isn't. First of all, check what kind of battery your vehicle features at the moment: AGM, gel, lithium, sealed, or flooded. Then measure the length, width, and height in either inches or millimeters. After that, locate the battery label for the Ah and CCA values.

Cold cranking amps is the maximum current said battery delivers for half a minute in cold weather, whereas amp hours indicate the capacity. Now that you're up to speed with 12-volt car batteries, locate your vehicle's battery and disconnect the terminals. First remove the negative (black) terminal from the battery, followed by the positive (red) terminal. You may need to use a socket wrench if there's a nut or bolt securing the negative terminal.

Now remove the battery hold-down to pull out the battery. Before installing the new one, take a wire brush to the terminals and cable ends to clean off any corrosion. You can further apply terminal grease to the terminals before reconnecting them to the battery. Positive comes first, negative after. The final step is to start the car and check if everything works as intended, beginning with the headlights. Certain vehicles equipped with start-stop systems may require programming or resetting with every replacement 12-volt battery.

Light paint scratches and scuffs

Yours truly remembers identifying the very first scratch on his very first car purchased new. It was a painful sight, but it also thought me that you don't need to spend big money at a professional detailing shop in order to remove light paint scratches and scuffs.

There are plenty of paint scratch removal products out there, although they're better described as clearcoat paint scratch removal products. If the scratch or scuff is too deep, you're better off repainting the panel. If not, choosing the right product is of utmost importance. Having tried a number of such products, I vouch for Meguiar's Scratch X or the Scratch Eraser Kit that comprises a bottle of Scratch X, a pad, and a microfiber cloth.

Apply scratch remover on the pad, then run the pad along the scratch back and forth using a drill. Lastly, clean the area with a microfiber cloth. Those without drills can work Scratch X into the problem area by hand using a foam pad or a microfiber cloth. While it does not perform miracles, the before and after beggars belief. And while you're at it, spend a few dollars on a good wax – be it carnauba or synthetic – for extra protection and gloss.

Foggy headlights

What is the primary purpose of the headlight? Lighting up the road ahead at night, followed closely by enabling other drivers to see where you are. Be it halogen or xenon-type bulbs, when your headlights get dimmer than normal, that's the signal to either change the bulbs or restore the plastic lenses to a crystal-clear finish. In the latter's case, it's a bit harder than replacing old bulbs.

Similar to scratch removers, there are many products available, yet Meguiar's two-step headlight restoration kit stands out. It should be mentioned that Meguiar's is owned by 3M, and 3M is known for quality products across a wide range of industries and applications.

First mask around the headlights, then use cleaning solution on a cleaning pad to clean the lenses using a back and forward motion. If there's still a bit of oxidation or yellowing, repeat the process. Now wipe the surface clean and check for a uniform frosted appearance. Wipe the lenses with a damp cloth, let them dry, then spray headlight coating onto the lenses to remove the sanding marks. The first coat should be left to dry for 5 minutes. The second coat will seal the headlight lenses. Within 24 hours, the final coating will be fully cured.