January 27th, 2010 admin
Performing An Engine Leak Down Test
The performance of your car’s engine is dependent on the air and fuel that is drawn into each of the combustion chambers during operation. When air and fuel enter a chamber, the intake and exhaust valves close, sealing both inside. Within the chamber sits a piston. It rises and compresses the air-fuel mixture. A spark plug sits atop the chamber and ignites the compressed mix. The resulting explosion forces the piston down and ultimately is responsible for propelling your vehicle forward.
If the pressure within the combustion chamber declines due to leakage, misfires and similar problems can occur. That will hamper your engine’s performance. A leak down test measures pressure loss within the cylinders. A mechanic will often use this test to identify whether a leak exists as well as its root cause.
Below, you’ll learn how a leakdown is performed and some of the potential problems it can help to identify. If you have the proper gauge, you can do the test at home. Otherwise, an auto technician can do it for you.
How The Test Is Done
First, you’ll need to remove your spark plugs. You’ll then need to position each cylinder’s piston at top center of its chamber. Second, connect the coupling on your leakage gauge to the hole in which your spark plug usually rests. Third, fill the chamber with compressed air and take a reading on the leakage percentage.
It’s important to realize that there will always be some measure of leakage from each of the chambers. If the gauge shows less than 10%, your engine is fine. If the leakage percentage is between 10% and 20%, it’s still in good condition, but you’ll want to note any changes in its performance. If the gauge shows 30% or more, you have an engine problem.
Identifying Potential Problems
One of the advantages of a leakdown test over a compression test is that it’s easier to identify where the lost pressure is headed. This is important if fixing a leakage requires taking apart your engine.
For example, if you hear air leaking out of your car’s tailpipe, the problem is likely your exhaust valve. On the other hand, you might notice a whistling sound coming from your intake; that signals a leak in your intake valve. Hissing from your PCV valve suggests the piston rings are failing.
If you look at the top of your radiator reservoir (take the cap off) and see bubbles, it could mean a leakage problem with your head gasket.
As noted, a leakdown test is easy to perform at home. You’ll need a leak down gauge, a source for the air that you’ll send into each cylinder’s chamber, and a few tools (e.g. a socket to remove the spark plugs). Armed with those resources and a little free time, you can perform a leakdown to find the root cause of a pressure loss.
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May 5th, 2009 admin
Three Main Parts Of Your Car’s Cooling System
Every minute you’re driving, your vehicle’s engine goes through its combustion process thousands of times. As it does, it produces intense heat. Nearly half of that heat leaves through the tailpipe and dissipates in the air. The other half must be absorbed by the parts that comprise your engine. That includes the cylinder heads, pistons, and other components.
On their own, these parts cannot withstand the high temperatures generated by combustion; they would start to malfunction and eventually fail completely. Luckily, your car has a cooling system. It is specifically designed to help these components soak up the excess heat without their being destroyed in the process.
Below, I’ll give you a brief overview of the three main parts that make up your vehicle’s cooling system. I’ll explain the job they do and how they help ensure your engine doesn’t overheat.
#1 – Water Pump
The “secret” behind your cooling system’s effectiveness is the coolant. It circulates throughout the engine and surrounding components, absorbing much of the excess heat along the way. Then, it travels into the radiator which is cooled by constant airflow.
In order to circulate, the coolant must be pumped along its path. This is the job of the water pump. It’s powered by your car’s timing belt, though older models might have a flat belt that powers the pump. If the timing belt breaks, it cannot operate the water pump, which will ultimately prevent the coolant from circulating and absorbing the heat.
#2 – Plumbing
By plumbing, I’m referring to the auto parts through which the coolant travels. That includes a network of hoses, valves, and the radiator. It also includes the heater core, but that’s less important for this discussion. We’re mainly concerned with the hoses. Because the hot coolant travels through them continuously, they deteriorate quickly. A lot of car enthusiasts recommend replacing the hoses every three years. However, you should check them for cracks and fissures every four months. The hoses are relatively inexpensive, so if you notice crack – even small ones – replace them.
#3 – Sensors And Thermostat
Your car’s cooling system is equipped with sensors, fans, and a thermostat to monitor and control the temperature around the engine. They work together as a team to help make sure the temperature does not exceed a certain limit. If any of these parts fail, the temperature can rise higher than normal. When that happens, your vehicle’s performance can be hampered and emissions will likely rise.
It is impossible to overstate the importance of your vehicle’s cooling system. When all of the components involved work properly, your car’s engine will perform its combustion process without problem. However, if the water pump, hoses or valves, or sensors or thermostat malfunction, your vehicle can overheat. And that can easily lead to expensive engine damage.
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April 30th, 2009 admin
Common Mistakes Car Buyers Make
Automakers, desperate to sell their inventories, have begun offering attractive incentives to lure prospective buyers. But, finding an automotive bargain can still prove elusive. Car dealerships can easily confound buyers and secretly hide pockets of profit. For the unwary, a trip to the auto dealer may begin as a bargain-hunting expedition, but end up as an expensive lesson in car shopping.
In this article, I’ll give you three important tips that you should use when shopping for your next vehicle. These tips will help you save money, save time, and negotiate objectively to get the best deal.
#1 – Set Your Emotions Aside
You visit the dealership lot and your eyes settle longingly on the gorgeous red automobile gracing the nearby pavement. You must have it, no matter the price. Slow down and take a breath. Buying a vehicle is a substantial investment. Unless you’re paying cash, you’ll be making monthly payments for several years. Will you feel the same way about the car three or four years down the road? Or, are you merely suffering from love at first sight?
#2 – Keep The Numbers Separate
If you’re hoping to trade-in your clunker to have the value applied to your new automobile, be careful. When it comes to numbers and amortization schedules, the dealer’s salesperson is king. Too often, prospective buyers will blend the negotiations. Predictably, the salesperson will offer what seems to be an incredibly generous amount on the trade-in. The buyer, reeling from his good fortune, practically falls into the seat of his new vehicle. Unknown to him or her, the dealer’s profit is built into the monthly payments.
Negotiate the transactions separately. Begin with cementing the price of your new automobile. Then, work on the value of your trade-in. That way, you’ll know whether you’re truly getting a good deal (on both transactions) or if you’re being taken around the block.
#3 – Shorten The Financing Terms
One of the strategies that auto dealerships are using in order to entice people into buying new vehicles is offering a 7-year loan. At first, it sounds great; a longer loan means lower monthly payments. The truth is, longer financing terms translate into a higher cost for you and more profit for the dealer. In other words, they’re not offering it to be nice.
If possible, say no to the extra long loan. Instead, opt for shorter terms that allow you to pay off the loan more quickly. You’ll pay less interest and when the time comes to sell your car, you won’t find yourself owing more than it’s worth.
Even though the car-buying landscape has shifted in favor of the buyer, you should still be wary of making a purchase decision too quickly. Remember, set your emotions aside, keep your trade-in negotiation separate, and avoid the extra long financing. By the time you leave the dealership lot, you’ll be confident that you weren’t taken for a ride.
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