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Auto Repair Basics

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Learn Auto Repair Basics

Auto Repair basics covers some of the must know information for anyone who has a car or truck, and will certainly need auto repair at some point. Learn some basic auto repair tips that will save you a lot of money in costly auto repairs.

Auto Repair

Auto repair includes a variety of topics from basic auto repair and why your engine won't start to performance issues and maintenance like alignment, brakes, exhaust, oil changes, and transmission problems. In this auto repair article, we will discuss many of these topics briefly to help you better understand the problems and how to fix your car or truck. Some sections of this article may have links to full articles on the auto repair topics, or they may be in the list below this post.

Why don't the engine start? - Auto Repair Basics

Since an engine that won't start is the biggest topic in auto repair that tends to be asked or should I say demands attention, we will begin with fixing an engine that won't start.

Why doesn't the engine start? To answer this question and repair the issue, you must understand the reasons the engine won't start. There are three basic things required for your engine to start. These are fuel, spark, and air. Without all three of these, your engine will not run or start and will require an immediate need for auto repair.

The engine will not start if there is no fuel in the cylinders to ignite. Therefore, you must confirm fuel to the engine cylinders. You may need to confirm each cylinder is getting fuel. If you find that the engine won't start due to no fuel, you will want to confirm where the fuel problem begins. This can be done by checking to see if the engine is getting fuel to the rail or carburetor.

Fuel at the rail identifies the lack of fuel for starting is in the carburetor or injector. Keep in mind that injectors require power and you should check their plugs and fuses. However, if there is no fuel at the rail, you may have a clogged fuel filter, bad fuel pump, or no power to the fuel pump. Start by checking to see if you hear your fuel pump when you turn your key to the on position. If yes, check the fuel filter, but if no, check your fuses and relays to confirm power to the fuel pump. These steps will identify for repair most auto repair issues related to lack of fuel that cause the engine to not start or idle rough. However, there are some sensors that effect fuel flow and may give an error code causing the check engine light to come on.

The engine won't start if there is no spark to ignite the fuel in the cylinders. This can be on all cylinders causing the engine to not start, or localized to one or more cylinders causing rough idle. You can check each cylinder by pulling the spark plugs and checking for spark, or see if they are wet with fuel. No spark is generally due to plugs, plug wires, distributor cap/rotor, coil/coil-packs, or timing sensor on the flywheel. These problems generally throw an error code and turn on the check engine light.

Note that both the fuel and spark require electricity. In some engines (generally small engines) there is no fuel pump or injectors and/or battery. These engines use gravity feed or vacuum to feed the fuel, and the magnetic rotor with a coil to produce the electricity for spark. In both, the general principals are the same, however, in most auto repairs, you will have a battery, generator/alternator, fuses/relays, and an ignition switch. This is why power can effect either fuel or spark, or both. The battery is the primary supply of power to these systems, but may only supply the starter, but you should confirm the battery charge and connection. Check fuses and relays for the fuel pump, injectors, computer, ignition (key and control module). Also, note that in some cars and trucks, the alternator can prevent the engine from starting.

The engine won't start or stay running without air supply. Spark ignites the fuel, but fuel burns with oxygen. Blockage of airflow can keep the engine from starting, but generally starts and dies quickly, and limited airflow reduces power and can flood the cylinders because the fuel is unable to completely burn off. This should produce an error code and turn on the check engine light. You should check your air intake and filter. Mice like to build nests in these areas and it can clog or limit air into your engine. Also confirm the exhaust flow. If the exhaust is unable to pass, there is no new air drawn into the engine. This issue is closely related with sensor problems (mass air flow sensor, IAC or Intake Air Control sensor, or throttle positioning sensor). These sensors control the amount of fuel to air in the mix and regulate the idle and determine the power the engine has. You will often stall out or have no power to gain speed.

Wheel Alignment - Auto Repair Basics

The next most common auto repair is related to the alignment of the wheels. We all think about the alignment when the vehicle starts pulling to one side or the other or when the car begins to shake in higher speeds, and while this can be the problem, the car may be pulling due to problems with the brakes and the shaking can be a damaged or unbalanced tire.

A more identifiable method to diagnose wheel alignment issues is to consider if the vehicle is pulling to one or both sides or shaking more as speed increases, and to inspect the tires. Due to the adjustments possible for a wheel, it is able to pull to both sides at the same time and can be in balance allowing the vehicle to drive straight. The wheels can be angled in/out to the top and bottom or the back and front. Either of these can result in shaking or pulling, but will always cause wear on the tires. You will often see the inner or outer edges of the tire tread are worn more than the rest, but some times in the center. These are a good indication the wheels are not in line with each other, and can be a sign of more dangerous damage to your steering. I would recommend having it inspected by a professional. While you may know someone who can replace the damaged parts, getting them aligned correctly is important to not damaging the new parts.

Diagnosing Brakes - Auto Repair Basics

The next most common auto repair is fixing problems with the brakes. As I just mentioned, an often overlooked or misdiagnosed problem with the brakes is when the vehicle is pulling or shaking. The car or truck may pull to one side or the other while driving or when the brakes are applied. This can be a sign the brakes are damaged.

If the vehicle pulls while driving, it can be the alignment or the brake is not disengaging on the side it pulls towards. This is often due to a bad caliper that is stuck, a bent brake pad, or a bent mounting bolt (slide bolt), and in some cases, it may be pulsing due to a warped rotor.

If the vehicle pulls when the brake is applied, the problem is generally on the opposite side of the direction the car pulls towards, but can be on the same side if parts are bent and causing the brake to apply harder on this side. Check the opposite side to see if the brakes are engaging, leaking, or need air bleed out of the line/caliper. You may have a leak or a bad caliper. If this side is working fine, check the other side for bent parts that are making it engage harder. If you find no damaged brake parts, it may be in the hydraulic pressure distribution.

Another common brake problem seen in auto repair is soft or spongy brakes or brake peddle. This is often due to air in the lines and/or low brake fluid. Check and fill your brake fluid and close the cap on the reservoir. Then pump your brakes a few times and hold for a few seconds. Then wait a minute and repeat this a few times to see if the problem is fixed. If not, you may need to bleed the brakes to remove air. Then refill the reservoir and repeat the previous steps (bleeding brakes generally requires 2 people). If the brakes are still soft and spongy, you may have a bad master cylinder or a leak.

When you hear noises coming from your wheels, it is most often the squall tabs on the brake pads or a glazed rotor. As some people may have you believe that the squall tabs are just a warning that your brake pads are almost gone and you have time to replace them, this is not even close to true.

While the squall tab does start to rub before the pad is gone, it is only a last resort warning while still having the ability to stop the vehicle and before the rivets that hold the pads are ground off. To drive like this damages the rotor as the steel tab cuts into the rotor, and will damage other parts of the brakes when the pads are gone. Seek immediate repairs when the tabs begin to make noise, or monitor and replace brake pads before damage occurs.

If the rotor is glazed, it is also likely warped. This is because glazing occurs when the rotor gets extremely hot and cooled rapidly. When the rotor is glazed, braking is reduced, and if the brake rotor is warped, it can cause damage to the other parts of the brake system.

Often squalling or even growling noises come from the wheels and are misdiagnosed auto repairs. Many shops will start with the brakes, especially if they see worn pads, but when this doesn't solve the problem, they may check for other problems. While it can be brakes, or rather, the brakes may also need fixed, this is also likely to be worn bearings.

Worn bearings is a less common auto repair, but rather important if you don't want to see your wheel pass you going down the road. (Yes, it can.) Worn wheel bearings can grind/growl as you are driving, but generally before they get that bad, you will notice the growling as you turn. They don't always both go out at the same time even if they are both close to worn. More often, one side gets a small piece of sand or debris in the bearing and it destroys the bearing on that side. There are caps and covers to prevent debris from getting in here, but sometimes the grease is just low and the debris comes from these parts. If you hear grinding, growling, or squalling, start your check here. Bearings are cheap, but the damage caused by a bad bearing is not. If you have a high mileage vehicle, I would recommend replacing the bearings or at least repack them with new grease. (A tip for you: this is heavy grease. pack them well but don't wash your hands until you have wiped all of the grease from your hands with rags. Water will make it like glue and very difficult to get your hands apart. )

Exhaust Problems/Check Engine Light - Auto Repair Basics

Basic auto repair maintenance can prevent most problems with your vehicle emissions and exhaust. Excessive use of fuel treatments, limited air flow, and unburned fuel can damage your catalytic converter. Generally, the check engine light will come on due to an error code long before damage occurs. Do Not Ignore This Light! Unburned fuel is generally the result of low or no spark (misfire) or limited air flow.

Most of the time, a basic tune up will fix your problems. This is spark plugs, plug wires, distributer cap, air filter, and fuel filter. However, in some cases regarding the air fuel mixture, you may have various sensors causing the problem. Some that will effect this and cause the need for auto repair are the throttle positioning sensor, mass air flow sensor, and the O2 sensor. If any of these sensors are giving the wrong input to the computer, the computer adjusts the air flow incorrectly and can throw the O2 sensor code error and dump unburned fuel into the exhaust.

Fix Stuck Valve/Low or No Compression - Auto Repair Basics

One other issue that can damage your exhaust system is oil in the exhaust. This can happen due to a stuck valve. A stuck valve is a major auto repair that can be easily fixed most of the time, but will allow oil in the cylinder and can cause a misfire or lack of compression in a cylinder. This is easily construed as a need for a complete engine rebuild by many auto repair shops. Don't panic, and read the next section. Most of the time a stuck valve can be fixed and restore compression to the cylinder.

While an oil change is the most recognized maintenance for your car or truck, most people don't understand all of the things changing engine oil does or how it can prevent more costly auto repairs. It is commonly understood that the oil keeps the moving parts lubricated and allows them to move freely, and some people assume that as long as there is oil in the engine, it is performing this task. While this is true to some extent, it is not fully accurate.

Over time the oil gets hot and breaks down reducing its ability to perform this function. Also, metal shavings, carbon, and other debris build up in the oil and on the surfaces of the engine. Most of this debris is caught in the filter until it is clogged and no longer allows good oil flow to prevent damage. The resulting effect is the lower flow of oil through the engine allows more to be burned to the surfaces of the parts. This becomes an issue with all moving parts of the engine and will eventually stop them from moving. One of the first places you will see this is in the oil pressure gauge (lower pressure/higher pressure), and the first moving parts to stop moving are the valves.

This is a common auto repair with high mileage vehicles, but is often not noticed until your check engine light comes on and you find low or no compression in one or more cylinders. If it has progressed to the point of no compression, the rings and piston are likely destroyed and will require a full rebuild to fix the engine. If the problem has not reached this point, you should be able to fix the problem and restore the flow of oil to reduce/prevent further damage, and restore compression in the cylinders.

This is done by changing the engine oil and filter and allowing the clean oil to circulate through the engine and clean and lubricate the engine. Run the new oil for a minimum of two hours, then you can use an additive to help clean the build up that is causing the valves to stick. Use no more than directed or you will cause problems. (I use an additive, and I think is calls for about an ounce for my engine).

I use the additive in my oil and run it for 2-6 hours of drive time, then change my oil again. I do this every time I get ready to change my oil to prevent new buildup, and it seems to work as my last truck worked great until I sold it at over 400k miles. There are a lot of product out there that may work better. I don't know.

You will also want to note that the new oil contains conditioners and detergents. The conditioners help keep your seals from cracking and developing a leak.

Transmission Repair/Transmission Slipping - Auto Repair Basics

Probably the most feared auto repair is transmission repair because most people know very little about transmissions and their problems or how to prevent or repair them so, we will start with some basics about transmissions and transmission repair.

Transmissions have an oil and filter that need to be changed about every 50k miles. So, if you are looking at a vehicle to buy that is high mileage, you will want to check the transmission fluid to see how clean it is. Dark transmission fluid on a high mileage vehicle has likely never been changed. What makes the fluid dark is the shavings and debris in the fluid. This debris comes from the break down of parts like the clutch pads inside of the automatic transmission. The more debris circulating, the faster the damage occurs. So, dark or burned smelling transmission fluid is likely to result in transmission failure soon and require a replacement or rebuild of the transmission. If the transmission fluid is not bad, you will probably want to get it changed soon so that you know when it was last changed and to prevent damage. However, if you already bought a vehicle with dark fluid and high mileage, it may be best to try your luck. Often, when you change transmission fluid and filter in these vehicles, they lose their grip. That is because the sludge in the fluid is actually helping the transmission parts grip rather than slide, and new fluid will lubricate and make them slide.

Unlike engine oil, transmission fluid doesn't burn off or get used up anywhere. If the fluid is low, there is a leak, it was never filled, or you are reading the stick wrong. Each vehicle has a different method for checking the transmission fluid level. Many require being hot in idle and neutral/park depending on the make. Be sure you are checking the level of transmission fluid per the specs of the vehicle. This is often printed on the dipstick.

The amount of fluid in the transmission must be correct. High or low fluid causes a wide range of problems. Both can cause damage to the transmission.

High levels increase the pressure within the transmission and will prevent shifting, disengaging, or bust a seal and cause a leak that will then result in low levels of transmission fluid.

Low levels will reduce the pressure and lubrication. This will result in damage to parts, and can cause the transmission to slip or slip out of gear. When an automatic transmission slips/slips out of gear, you need to check and add fluid immediately to prevent damage, and you need to get the leak fixed quickly before the problem gets worse.

When you shift into gear and there is a slight delay before it engages and sometimes a clunk, it is because the transmission is slipping. You are likely to only notice the problem at this point when the transmission fluid is getting very low as this is a slight delay. The longer the delay, the worse it is. You are also likely to have been noticing your engine revs up for a second before engaging on occasion, or loss of power while driving. The loss in power while driving is more frequent when stopping, accelerating from a stop, or turning, and on incline/declines. This is because the transmission fluid shifts due to the incline/decline or inertia from the stop, acceleration, or turn, and causes the transmission to draw air instead of oil and it loses the pressure to engage the transmission bands that engage the gears. When you catch this problem early, you may not have major problems, but left unrepaired will get worse and eventually completely fail and damage the inner parts of the automatic transmission. Also, if this does happen, after you add fluid, it is important to circulate the fluid through the entire transmission. To do this in some vehicles, you must start the engine and shift through all gears. This includes reverse, neutral, drive/overdrive, and your low gears 1,2/L1,L2. Do this before driving.

The last thing that I am going to discuss here about transmission repair or rebuild is the modifications. I am not a fan of this practice. If there is even a slight mess up in the drilling of new valves inside of the transmission to improve performance, you will have to get a new transmission. The shops sell this to charge more, and get people to take this risk thinking they will get more power. The original designs work fine and last on average 100k-150k miles. Why change it? You already know the existing design works.

Replacing or Servicing/Restoring Lead Acid Battery - Auto Repair Basics

Another major issue when it comes to auto repair is the battery, because your car doesn't work without one, is the easiest auto repair to fix, but always happens at the most inconvenient times. Replacing the battery often costs about $100 for the battery, and is replaced more often than needed.

When you go into almost any shop, they test your battery to see if it is weaker than the ratings on the side or if the date is past the expected life of the battery. This is because it is the easiest part to replace that they can get an easy up charge for replacing, and because so much relies on the battery, it can fix a wide range of issues. However, just because you are losing charge or the battery doesn't meet its rating, doesn't mean the battery is bad.

Most cars and trucks use a lead acid battery, and many of these batteries are serviceable and require servicing. To service your car battery, you need to inspect the battery for swelling or bulging and cracks. Cracks may only be slight whitish areas in the plastic case of the battery where bulging has occurred. Check the sides, bottom and top for swelling. Then carefully check all around the positive post of the battery. If any area shows signs of swelling or cracks, then you should replace the battery.

However, if the battery case is in good shape and is a serviceable battery, you can open the covers and refill the battery acid. This is not a task for everyone. It is very dangerous and requires safety equipment like real rubber gloves, goggles, an apron, and baking soda to neutralize acid if needed. If you are up to the challenge, the cost of a box of battery acid from the local parts store is under $20. You should only need the smallest box (about $10) for most top offs or maybe 2 of them if your battery is really low. Do not over fill. There needs to be some space in the battery for the acid to expand as it gets warm, or you will over flow when the battery starts to charge.

As for any part of this article, it is for informational purposes. You should be the judge of your aptitude and abilities.



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