How Your Car’s Air Conditioner Works

Once an expensive luxury for the well-heeled, air conditioning is now a commonplace comfort in nearly all types of vehicles. A car’s A/C unit cools and dehumidifies air which enters the cabin. The first systems were relatively simple and easy to repair, but the introduction of computerized temperature control and other assembly modifications has changed that. Today’s do-it-yourself auto enthusiasts are rarely able to repair the units.

Below, we’ll take a brief tour through your vehicle’s A/C unit. We’ll explore the components that work together as well as the refrigerant which cools the air. The information I’ll provide is merely a glimpse. While you won’t be able to repair your vehicle’s A/C, you will at least be informed when you visit your mechanic.

How The A/C’s Components Work Together

The heart of your car’s A/C system is the compressor, a belt-driven pump that compresses and moves the refrigerant. A refrigerant is a chemical compound that is used to transfer heat, during which it undergoes a phase change from gas to liquid and vice versa.

Along with the compressor, the condenser is necessary for heat dissipation. As the refrigerant leaves the compressor, the heat absorbed from the cabin causes it to expand into a gas. Traveling along the condenser coils, the fluid proceeds to change back into a liquid. Because a condenser requires maximum air flow to enable heat dissipation, the part is often mounted in front of the radiator (though its position can vary). In addition to the mounting point, some vehicles have incorporated a cooling fan as well.

The evaporator also plays an important role in your vehicle’s air conditioner. This device removes heat from the inside of your car and provides a small degree of dehumidification. The evaporator assembly has an array of aluminum fins that allow water contained within the air to condense. When the water condenses, pollen, dust, and other particulates are trapped by the droplets which are then drained off and released under the car.

Refrigerant Maintenance

When the first air conditioning units were introduced, the refrigerant R-12 was used. Otherwise known as Freon, this odorless, colorless chlorofluorocarbon was discovered to damage the ozone layer. Since the 1990s, most Freon applications have been phased out due to government regulation.

In the event of an air conditioner malfunction on an older car, the fluid may have to be replaced with an environmentally-friendly alternative. Currently, this means retrofitting the old system for R-134a, a refrigerant that won’t harm the ozone layer. However, this new fluid will have a higher operating pressure and will therefore require new, stronger parts. In some cases, parts may not necessarily have to be replaced depending on the fluid change.

If you notice that your car’s A/C system isn’t cooling the cabin as quickly or effectively as it used to, ask your mechanic to run a test. It’s likely that the refrigerant needs to be replenished. That said, if your A/C is failing, plan to spend at least $200.

Basics Of Replacing Your Timing Belt

There are a lot of circumstances – and not all of them are car-related – that can potentially prevent you from getting to work in the morning. Your car’s timing belt is one of them. Most people have heard of them, but are still not entirely clear what they’re for or what they do. Frankly, they’re just glad to have a mechanic who knows what they’re doing when replacing it.

Essentially, this part plays a critical role in the management of the cylinders inside your car’s engine and at what rate those cylinders are ignited. Without this crucial functionality, your engine simply cannot run. That’s the main reason why you need to periodically inspect it to make sure it’s in good working condition.

Does it Need to be Replaced?

The easiest way to verify whether or not you’re due for a replacement is to check your car’s owners manual. (If you’ve been reading my articles, you’ll know that I keep pressing this point.) Depending on your car’s make and model, a different mileage point will be suggested at which you should have your timing belt replaced (or, at least inspected).

That interval is typically between 60,000 and 90,000 miles, but it can be less or more in some cases. If you don’t have access to your owners manual, you can either try to locate the information online, or simply visit to your local auto parts retailer and they should be able to tell you. They’ll have large reference manuals in which they can find the information.

Often, a lot of drivers make the mistake of assuming that since their timing belt is “squeaking” that it needs to be replaced. Despite what your mechanic may tell you, that’s not always the case. It’s not uncommon for it to make a bit of noise in very cold conditions, or in older vehicles. However, if you’re concerned, consider visiting your mechanic. He can usually tell very quickly just from looking at the part whether it needs to be replaced.

The Cost of Replacement

If it turns out that you do need to have the timing belt replaced, expect to pay approximately $30 to $40 for the part itself. That’s only an estimate; the price will vary slightly based upon the type of vehicle you’re driving. Also, it’s likely that you’ll end up paying approximately $100 to $150 for the labor involved. Ultimately, budget about $200 total to have the work performed.

Your car’s timing belt will eventually need to be replaced. The bottom line is that you should always check your owners manual. And when you have a few minutes, pop the hood and inspect the belt yourself.

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