Posts Tagged ‘ Car Repair Tips ’

 
Monday, November 3rd, 2008

How To Know Your Car’s Alternator Is Bad

Your car’s alternator is a part of the vehicle’s charging system. If you turn the ignition and the battery fails to crank the engine, the problem may be with the battery itself. However, it’s also possible that the alternator is no longer capable of holding a charge. When there’s a problem with the alternator, the battery will be unable to send a current to the engine. In this article, I’ll explain an easy way to identify whether your car’s alternator is going bad (i.e. not charging properly). I’ll also describe a few factors that can cause your alternator to become incapable of holding a charge.

Identifying The Problem

You can usually tell whether the charging problem is your battery or the alternator by watching your car’s headlights. Here’s how: start your car and turn your headlights on. With your car in “Park,” gently put pressure on the gas pedal. If you don’t see any change in your headlights’ intensity, your charging system is working properly. However, if you notice that your headlights become dimmer when you press on the gas pedal, it means that they’re being powered by the battery. Your alternator isn’t producing a current.

On the other hand, if the headlights grow brighter, it means your alternator is producing a current, but not very much. In fact, it may not be generating enough to keep the battery properly charged when your car is idling.

This method isn’t infallible for identifying a bad alternator, but it works most of the time.

What Can Cause A Bad Alternator?

Even though alternators are generally sturdy, there are many reasons why they can stop charging properly. They’re often susceptible to heat. If you’ve been driving long distances in extremely warm weather, they can lose their ability to produce a current. They can also be damaged from voltage irregularities. For example, if you jump start a car and cross the jumper cables, the current can overload the alternator.

Also, its ability to produce a full current can be affected if one of the diodes goes bad. The diodes are essential for converting the output from AC to DC. If one of them is damaged or burns out, the alternator’s output can be diluted.

If your alternator becomes incapable of holding a charge or producing a viable current, take your car into a service center to have the unit tested. If there’s a charging problem, you probably won’t be able to have it repaired. Most technicians will consider doing so to be too much effort. In that case, plan to invest in a new or remanufactured unit.

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Tuesday, October 28th, 2008

Car Repair: Basics Of A Valve Job

If you put a lot of miles on your car, or you’ve purchased a used vehicle that already has a lot of mileage, you’ll eventually need a valve job. The valves open and close, controlling how much air and fuel reach your engine’s cylinders. When there’s a problem, it can have an impact on your engine’s power. Cars usually need to have the valves looked at after reaching 80,000 miles. If neglected, you’ll likely notice the performance of your car declining. Below, I’ll describe a few reasons to have a mechanic look at your car’s intake valves. I’ll also provide a brief overview of a valve job.

Reasons To Have A Valve Job

A lot of older model cars that have a lot of mileage can experience problems with the intake valve. Because the valve plays a key role in allowing air and fuel into your car’s engine (through the cylinders), a problem can slowly deteriorate the power of your engine. Also, if a crack occurs in the cylinder head, coolant can reach the combustion chamber. When that happens, it can damage your engine’s cylinders. Finally, if your car has a burned intake valve, the engine may begin burning oil (you’ll likely be able to smell it). If you continue to drive with a faulty valve, you’ll notice a reduction in horsepower and even smoke billowing from your car’s exhaust.

What Is Involved?

A car technician will start by taking apart the cylinder head. He’ll want to check for tiny cracks or any signs of warping. If he finds any cracks - even small ones - he might be able to repair them through welding if the head is aluminum. If the cylinder head is made from cast iron, he may be able to fix the cracks with pinning (i.e. threading pins to seal the cracks). If he’s unable to repair them, the head will need to be replaced.

Once the cracks in the cylinder head have been repaired, it will usually be pressure tested for any leaks. Then, the technician will test the head for flatness to ensure it fits seamlessly with the head gasket. The valves and seats are then examined to check whether they need to be replaced or relined. A lot of repair shops will simply replace the valves instead of repairing them. Doing so helps to prevent failure due to overheating. Also, if the head’s seats are worn too badly, they’ll be replaced, as well.

Finally, the technician will look at the valve springs, including the retainers, to ensure they can provide sufficient pressure. If they’re damaged in any way, they’ll be replaced. Once all of the parts have been inspected, repaired, or replaced, the components are reassembled and the valves are “shimmed” to make sure they’re the right height.

Some drivers aspire to doing their own valve jobs. While it’s certainly possible with the proper equipment, it’s time-intensive and requires precision. Unless you’re unusually familiar with your car’s engine and cylinder head, you should have a trained mechanic perform the job.

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