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The 4-stroke combustion process (intake, compression, power, and exhaust) normally occurs smoothly. The pistons, spark plugs, fuel injectors, and other components work like a well-oiled machine. Pressure builds within the combustion chamber until the air-fuel mixture contained within it is ignited by the spark plug. That’s what propels your vehicle forward. When you hear a knocking sound as you accelerate, especially during heavy load, that means there is something wrong with your engine. This is called spark knock. And it can lead to expensive damage.

In this article, I’ll explain what is happening inside your engine to produce the knocking or pinging sound. We will examine the issues and provide some tips to fix the cause of the problems.

What Is Spark Knock?

The knocking sound is due to the fuel within your vehicle’s combustion chamber detonating. Rather than burning cleanly, it explodes under load, over and over. This occurs due to erratic build up of heat and pressure inside the chamber. It is not being controlled properly, and the excess heat and pressure is igniting the gas.

You might not immediately notice a change in the performance or output of your car engine. However, over a period of time, the spark knock can cause problems such as cracked rod bearings, broken rings, and head gasket problems. Each of these problems can be expensive to repair.

Reasons Knocking Can Happen

So, why does detonation happen? It can occur when your car’s exhaust gas recirculation (EGR) System malfunctions. The EGR valve is tasked with opening when you’re pushing your engine under heavy load (for example, if you’re towing something up a hill). By opening, it allows excess exhaust to flow out of the combustion chamber, lowering the temperature. If the EGR fails, this process cannot happen.

Detonation can also happen if your car’s knock sensor malfunctions. This sensor is supposed to identify situations in which the fuel is igniting erratically. It then tells your car’s computer to change the ignition timing in order to compensate. A failed sensor prevents this from occurring.

If your vehicle is older, detonation can be caused by carbon buildup. This happens when the carbon accumulates inside the combustion chamber on the pistons. This issue is easy to resolve by having a mechanic flushing the injectors and combustion chamber to clear all carbon build up and deposits.

Low-octane gas is another common cause of detonation. Some gas station owners label their pumps with “87″ when the octane is actually lower. Try filling your tank with a premium grade fuel from a respected brand (for example, Chevron).

If you hear knocking when your engine is under heavy load, take your vehicle to an experienced mechanic as soon as possible. He’ll have the necessary Equipment to test your engine and identify the root cause of the fuel detonation. If you ignore the problem, you could be setting yourself up for expensive repairs in the future.

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Your car’s alternator won’t last forever. Neither will your catalytic converter. Actually, your fuel injectors, ignition switch, and muffler can fail as well. Every auto part under your vehicle’s hood can unexpectedly expire and need to be replaced.

If you take your car to the dealership, they’ll use Original Equipment Manufacturer (OEM) parts. Conversely, the mechanic at your local garage is most likely going to use aftermarket alternatives. Which is better?

Claiming one choice is always better than the other is overly-simplistic; it ignores subtle pros and cons of each. Below, we’ll compare the advantages of investing in OEM parts versus buying their aftermarket equivalents.

The Advantages Of Aftermarket

Aftermarket components and systems are less expensive than their OEM counterparts. However, the percentage you’ll save will vary by the item your vehicle needs. Be cautious. A lot of aftermarket units seem low-priced, but hide defects that can leave you stranded at the side of the road.

Another advantage is that the quality can be just as high as Original Equipment Manufacturer Systems. The reason is because the automaker is often forced to offset the performance of the component with other factors. For example, consider anti-lock braking systems. The manufacturer has to make sure the pads don’t squeal; otherwise, customers will complain. The problem is, ensuring the brake pads are silent requires accepting a mild loss in performance (to that end, high-performance brakes are often noisy).

Yet another advantage of buying after-market components is that they’re widely available. Mechanics can easily obtain any replacement part your vehicle needs. In fact, they’ll often have them in stock.

The Advantages Of OEM

OEM parts also offer significant advantages. First, you’ll always know what to expect from them. They are nearly identical to the systems that were installed within your vehicle at the time it rolled off the factory floor.

Second, you won’t need to examine a given component in order to spot defects. Original Equipment Manufacturer parts are designed to be seamless replacements and possess a consistent level of quality. That means there is no reason to be concerned with compatibility and performance issues.

Third, they’re typically supported by a one-year warranty. For example, if you have your alternator replaced and it malfunctions within the first year, the automaker will replace it with another OEM alternator without cost. The experience might not be the same if the alternator were an aftermarket unit.

Which Is The Most Appropriate Choice?

There are a few reliable rules of thumb to follow. First, if you’re replacing anything on your car’s frame (for example, a body panel), you should opt for Original Equipment Manufacturer replacements. Second, if you’re leasing your vehicle, you should also choose OEM parts. Otherwise, you’re likely to lose your deposit when you return the car. Third, for key components (like an alternator or fuel pump), OEM is always a better choice.

On the other hand, if you’re willing to take a risk (and the risk can be substantial) in order to save a few dollars, aftermarket parts may be a good investment.

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Transmissions are one of the most complex Systems under the hood. In fact, that’s the reason many auto repair garages will refuse to work on them. Some might perform minor repairs, but will refer you to a transmission shop for anything more extensive. There are a lot of parts involved in making sure that the system runs smoothly and mechanics are loathe to cause bigger problems.

This level of complexity often makes transmissions one of the least understood components to drivers. Adding to the confusion, they’re designed differently. Some are designed for front wheel drive while others are designed for rear wheel drive. In this article, we’ll take a look at some of the differences. I’ll tell you all about your transmission’s job and help you understand the pros and cons associated with RWD and FWD.

Understanding Its Job

Your car’s engine generates power through its 4-stroke combustion process. That power must be delivered to your drive wheels in order to turn them. Also, it’s worth noting that your engine has a range of RPMs in which it operates at maximum efficiency. Your transmission has two jobs. First, it needs to deliver the power generated by the engine to the drive wheels. Second, it needs to perform this task while keeping your engine operating within its optimal range of RPMs.

It accomplishes this through several gears. In low gears, the engine must turn more quickly in order to power the wheels. In higher gears, it doesn’t have to work as hard. The transmission helps the engine advance from first gear to higher gears while keeping your car moving at higher speeds.

RWD Versus FWD

If your vehicle operates on a rear wheel drive configuration, the transmission will be positioned on the back portion of your engine. A drive shaft will connect it to the rear axle. As your engine generates power and turns the crankshaft, that power is transferred though the transmission to the drive shaft and ultimately, to the rear axle. The rear axle spins, which causes your tires to rotate.

While the concept behind the power flow is similar, a front wheel drive car works a little differently. The transmission is still located near the engine. With the final drive, it forms a transaxle. A front axle connects to the transaxle, which in turn delivers power to rotate the front tires.

To keep the explanation simple, I’ve ignored the torque converter. In reality, power travels from the engine through the torque converter into the transmission. The other components work as described.

Is One Better Than The Other?

Most modern vehicles are designed with front wheel drive. An FWD weighs less, costs less to manufacture, and usually delivers higher fuel efficiency. On the other hand, an RWD distributes the weight more evenly across a car’s frame, which improves braking ability. Plus, because the design is less crowded than an FWD, it’s easier to service without taking everything apart. In the end, when choosing between RWD and FWD, consider your driving needs and the factors on which you place a high priority.

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