Thanks for joining me for another installment of the Auto Specialist. Two recent news stories in the auto industry were particularly notable. The first involves Mexico’s latest foray into car manufacturing. The country was once a leader in light passenger vehicle output, but has lost major production contracts to Asia over the past several years. The tide might be changing in Mexico’s favor. Honda Motor Company recently announced plans to build an $800 million plant in the country to focus on the U.S. market. Other Japanese automakers are expected to do the same.
The second news story involves the automakers’ race to meet President Obama’s mandated CAFE standard by 2025. The new rules require car manufacturers to build vehicles that deliver 54.5 miles per gallon. While 2025 is over a decade away, there are major technological obstacles that need to be resolved.
In today’s segment, we’ll help Brent with a question he has about his Saturn’s fuel economy. We’ll also answer Serena’s question about the “Check Engine Light” on her Passat’s dashboard. Lastly, we’ll help Darren figure out why his CR-V’s engine keeps overheating. There’s a lot to cover, so let’s get started.
Question: I’m driving a 2001 Saturn SL1 with 109,000 miles on it. I bought the car new at the end of 2000. Back then, the gas mileage was great. I tracked everything, and the numbers matched the manufacturer’s claims. But over the years, my gas mileage has dropped. I still track the number of miles I drive, and the gallons of gas I purchase. I can see a major difference. Can you tell me why this happens?
Answer: Thank you for your question, Brent. The problem you’ve described is actually very common. Gas mileage can decline for several reasons, many of which involve the sensors in your car, and how your car’s computer responds to the data they send. For example, a failing oxygen sensor may cause the computer to send more fuel than necessary to the engine. A vacuum leak in the intake manifold can lean out the fuel mixture, causing a misfire. A failing engine thermostat might remain open, allowing coolant to reach the radiator after a cold start. This prevents the engine from operating at peak efficiency.
The bad news is that diagnosing and fixing all of the possible problems is expensive. The savings you’ll enjoy from better mileage is unlikely to warrant the expense.
Question: I own a 2007 Volkswagen Passat. It has about 53,000 miles. Last Wednesday, my Check Engine light went on, but I’m not sure what it means. Does the light mean there’s a serious problem with my engine? How can I tell?
Answer: Thanks for writing in, Serena. The check engine light can display for a lot of different reasons – some serious and others minor. For instance, leaving the gas cap open can set it off. On the other hand, the light may have displayed because your car’s head gasket has failed.
When the check engine light is triggered, a diagnostic code is stored in the computer’s memory. I recommend that you visit the dealer or a repair shop, and ask the mechanic on the floor to pull the codes. He should be able to figure out the problem by looking them up, and conducting a few tests.
Question: I have a 2005 Honda CR-V with just under 65,000 miles. My engine has started to overheat lately, which is frustrating since my car isn’t that old. I have no idea why it’s happening. What are some of the reasons an engine will overheat?
Answer: Thanks for sending in your question, Darren. In my experience, the most common causes are coolant leaks, a malfunctioning thermostat, and a failing water pump. That said, there are many other possible causes, such as a blown head gasket, bad fan clutch, and even a dirty radiator. I would suggest first looking for coolant leaks since they are the easiest to detect. If you’re unable to find any, have a mechanic take a closer look.
That’s it for today’s installment. Thanks again to Brent, Serena, and Darren for writing in, and giving us an opportunity to answer their car-related questions. Join us for the next segment when we’ll have a new batch of interesting car problems to troubleshoot. Until then, drive safely.