AUTO DOCTOR: Rainy-weather noise takes some probing

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By Junior Damato

Dear Auto Doctor: I am completely vexed with an unusual noise on my 2004 Mercury Grand Marquis. When driving in the rain I notice a clunk-clunk sound from the driver's door area. A body shop determined the door and window are tightly in place and could offer no help. I dread having to drive in rainy weather, as the noise is very distracting and I don't know if it's a serious problem. Any ideas? -Therese

Dear Therese: I would first road-drive the car when dry to determine if I could locate any unusual sounds. My next step would be a road test in the rain. Did you lubricate the rubber door seal? Is there any sign of rust at the door hinge or latch area? Do you get the noise if you wash or wet down the car? While driving in the rain did you try opening the window slightly? How about pulling the door release slightly or unlocking the door? These are all things I would try before getting into taking the door apart. Take the Mercury to another body shop.

Dear Doctor: I have a 1995 Infiniti J30 with more than 130,000 miles. It has been dealer-serviced since purchase. At times there is a tremendous smell of gasoline fumes, which lingers in the garage. Most times we use Sunoco (89) gasoline. The gas cap is always tightly sealed after filling. My wife seems to think that when we put the heater or AC on, the smell comes into the car. This problem started within the last two years. Do you think that we should use a higher octane? -Sal

Dear Sal: A gasoline smell without seeing any evidence of leakage is usually a sign of a rusty, leaking gas vent line. We use a hydrocarbon gas leak detector to locate leaks, as well as a smoke machine. I have seen rotted gas tank fill tubes cause this problem with leaking gasoline. I would not park the Infiniti in the garage until it is repaired.

Dear Doctor: I have a 1998 Ford Escort SE Sport Sedan with 2.0-liter engine and automatic transmission. The car runs without skipping a beat under any and all conditions. The car only gets 16-18 miles per gallon. This car should get 25 to 30 mpg. I have no engine service light warns and my OBDII [On-Board Diagnostic system] comes up with no codes either. Why do I get such awful gas mileage and what can I do to correct this or what should I look for? -Dennis

Dear Dennis: The first step is a check of the basics, such as air filter inlet, spark plug color (should be light brown), engine-running temperature (should be 190-plus degrees), and make sure there is no brake drag. The next step is using a professional scan tool to check the oxygen sensor operation. A timing belt off the tooth will also affect gas mileage in some cases without setting off the "check engine" light. You'll also have to make sure the odometer and speedometer are registering accurately.

Dear Doctor: I have a 2000 Nissan Altima with 92,000 miles. I took it in for service and was told that three motor mounts have to be replaced, as they are wearing away. He said the rubber section that surrounds the metal piece in the middle is corroding and that very soon the rubber will no longer support the metal piece properly and it will begin to move around, which is not good for supporting the engine. In your opinion, is nine years an average life span for a car's original motor mounts and is it now time to have them replaced? -Ellen

Dear Ellen: Engine mounts do wear; some are rubber and some are liquid-filled. Not all mounts need to be replaced when only one is worn. Go to your local repair shop and request a power brake test. The technician will place the car in drive, and then reverse while tapping quickly on the gas pedal with both the parking brake set and the left foot on the brake. Another technician will observe engine movement. It is not unusual to see dried-out rubber on engine mounts.

Dear Doctor: What are your thoughts on a new 2009 Toyota RAV4? I am in the market and have been looking at the four-cylinder model. -Ann

Dear Ann: The 2009 RAV4's four-cylinder now has plenty of power and the transmission shifts are firm and crisp. When I drove the four-cylinder RAV4 my average fuel economy was 28 mpg.

• Junior Damato is an ASE-certified master technician. E-mail questions to info@motormatters.biz or address questions to Auto Doctor, 3 Court Circle, Lakeville, MA 02347.