Q & A #86 With The Auto Specialist

Q & A #86 With The Auto Specialist

Welcome back to the Auto Specialist. Auto sales numbers for last month are still coming in, but it appears that Ford Motor Company was the pack leader. While the industry, on average, enjoyed brisk sales and an increase in volume over the previous month, Ford managed to outpace its competitors. A large part of the reason was its small vehicles. Demand for the Fiesta and Focus remained strong even though fuel prices have declined for the last several weeks. Consumers’ appetite for fuel-efficient cars seems as strong as ever.

Today, we’ll help Michael figure out the reason his Caliber’s air conditioner is failing to blow cold air. We’ll also help Cecilia troubleshoot a problem she’s having with her Sonata’s brakes. Lastly, we’ll answer Ben’s question about his Montero Sport’s engine. There’s a lot to cover, so let’s get started.

Question: I’m driving a 2007 Dodge Caliber with 51,000 miles. So far, the car has driven well. I’ve never had a problem, nor had to do much besides have the oil changed, and replace the brakes and tires. A couple of days ago, my air conditioner suddenly stopped blowing cold air. The air coming from the vents feels cool, but definitely not cold.

I use the A/C in my car whenever I drive, even when the weather is nice. So, this is causing a problem for me. I haven’t gone to the dealer since my warranty expired last year. Would you be able to tell me what might be causing this issue?

Answer: Thank you for your question, Michael. The problem you described can be caused by a number of components in your car’s air conditioning system. For example, the condenser may be clogged with debris, such as leaves and dirt. This component cools the refrigerant flowing through your A/C. If it is clogged, it won’t work properly.

The problem may also be caused by debris that is blocking the opening to the evaporator. This is the part that absorbs heat from the cabin of your vehicle – it also serves other functions – and further chills the refrigerant. If it becomes blocked, it will be unable to do its job. The result is cool – instead of cold – air coming through your vents.

Because of how the A/C is designed, there’s no way to know for certain what is causing the issue you’re experiencing without running a test. In addition to the condenser and evaporator, the problem may be due to a failing cooling fan, malfunctioning pressure switch, or a leak somewhere in the system. I suggest having a mechanic – independent or dealer – take a closer look.

Question: I have a 2005 Hyundai Sonata. It has a little over 69,000 miles. I keep hearing a scraping noise whenever I apply the brakes. When I take my foot off the pedal, the noise goes away. My dad says the noise is probably due to the brake pads having worn down. Does that sound right to you?

Answer: Thanks for sending in your question, Cecilia. Your dad is half-right. The scraping noise you’re hearing occurs when the wear material on the brake pads wears down to the metal. Once this happens, the metal begins to rub on the rotors – which are also made of metal – whenever you apply the brakes. The friction between the worn pads and rotors is causing the scraping noise.

Have the problem fixed as soon as possible. If you wait too long, the rotors will become severely damaged, and need to be replaced.

Question: I own a 2002 Mitsubishi Montero Sport with 104,000 miles on the engine. I took my car into the shop last Friday to have a few small things fixed. The technician did a compression test on the engine. He said the compression was high, and may be due to carbon deposits. He also said it could eventually damage the engine. Can you clarify what he meant?

Answer: Thanks for writing in, Ben. As you probably know, your engine’s cylinders rely on compression to ignite the air-fuel mixture in the combustion chambers. One of the results of this process is small carbon deposits. They accumulate over time, sticking to the sides of the chambers as well as the heads of the pistons. This increases the level of compression.

In high-mileage cars, this problem can lead to spark knock (also called detonation). This is a knocking sound that occurs when the air-fuel mixture detonates. It can damage the pistons, rod bearings, and even compromise the head gasket. Your mechanic should be able to offer a cleaning solution that will flush out the carbon deposits.

That’s it for this installment of the Auto Specialist. Thanks again to Michael, Cecilia, and Ben for giving us a chance to help with their car problems. We’ll have a new set of questions to address next time. Until then, drive safely.