Q. I have a 2005 Jeep Grand Cherokee with a 4.7 liter engine. The exhaust was normal for the first 15,000 miles; it then became loud and sounds like a hot rod. I had the muffler replaced, which toned it down some but it is still loud. The dealer has no answer or solution. Have you heard of anything like this?

— Bob

A. If there are no exhaust system leaks, it is possible the catalytic converter has started to fail. The inside of catalytic converters look like a honeycomb and will muffle the sound of the exhaust system. As the honeycomb breaks up, the engine will gradually get louder. If this is the case the catalytic converter should be under warranty.

Squealing while turning

Q. I own a 2002 Hyundai Elantra and it runs great, but during the last month I have noticed that when I make sharp right turns or back up while turning to the right I hear a squealing.

What could this be? Any help would be great determining this problem.

— Stephanie C.

A. The power steering belt may be starting to slip causing the squealing noise you hear. The best thing you can do is road-test the car with a technician so they hear the same sound that concerns you. This will eliminate any possible misdiagnoses. If it is the power steering belt, consider replacing the alternator belt as well.

Use the ‘clear flood’ mode

Q. My 1999 Audi A4 2.8, has been experiencing two problems: It usually takes a long time to re-start, or may not start at all, whenever I stop to refill gas, unless I leave the car running (which I heard from a few experts that is OK to do). I had an Audi specialist look at it two years ago who said there was some “air” escaping in the system. I changed the gas tank cap but that didn’t solve the problem.

The second problem is that for about three months, I’ve smelled a burnt oil-like odor through my A/C whenever I start the engine –or intermittently while driving. I had it checked twice and the body shop that did my oil change said it’s not an oil leak, but some other liquid that dropped on the manifold near my air vent. Unfortunately they couldn’t determine/locate this leak. If you could help guide me to how to solve or investigate these issues further, I would appreciate it very much.

— Ted, East Providence

A. It sounds as if the car is “flooding” after you fill the tank. You may be able to get the car going by holding the gas pedal to the floor and cranking the engine. This is referred to as the “clear flood” mode. If this does allow the car to start, have the repair shop look for a faulty emissions purge valve.

Regarding the oil smell, if there is something leaking on the hot exhaust this could cause the burning smell. One method to determine what’s leaking is to add an ultraviolet dye to the oil, power steering, or other fluids. Once the leak begins, a technician will use an ultraviolet light to trace the leak to its source.

How to avoid being ripped off

Q. My question may be difficult to answer. I would like to know how not to get ripped off at the car repair shop.

I am a single woman who doesn’t know a lot about car repair. On my recent trip to the Toyota dealer I had the 45,000 mile check-up on my 2006 Toyota Corolla. My first question is how important are these checkups for the car? I assume preventive maintenance would save money in the long run, but it cost $526. This price included a replacement cabin air filter along with a pcv replacement valve. The parts were only $130 but the labor was $350.

They also informed me that I needed new tires, as I was aware. I did a little homework and found a good price on tires at Firestone. When I was having the tires put on, the mechanic came out and told me I needed a fan belt and the cabin filter changed.

Are these mechanics replacing things that are not bad to make money from people like me who don’t know anything about cars?

— Lisa

A. Routine or preventative maintenance is important to prevent break-downs. Changing the oil, filters and checking the various mechanical items in the car will typically extend the life of the vehicle or at the least catch a problem before it turns serious and more expensive. Your vehicle’s owners manual is a great place to find a maintenance schedule. Although I don’t like to believe there are dishonest mechanics, the reality is some shops may oversell parts and services.

If you are not sure about a repair shop, start with a small repair (oil change or tire rotation) and decide how you feel about the shop. You could also ask your friends and neighbors for recommendations. Also look for the blue and white ASE ( www.asecert.org) sign. This sign indicates the technicians in the shop have voluntarily been tested on their knowledge of vehicle repair.

In my opinion, the best method to finding a reputable repair shop is to look for garages that belong to the AAA ( www.aaa.com) Approved Auto Repair network.

These facilities are checked continually by AAA, have certified technicians, and provide a 12-month or 12,000-mile warranty on repairs.

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