Dear Doctor: My 2006 Dodge Magnum has less than 37,000 miles. On cold days it whistles and makes a flute-like noise that disappears when the car gets warm. I had the belt changed, but that didn't fix the noise. I also had a smoke test done for any intake leaks -- and there are none. Do you have any ideas on what it could be? Arlene
Dear Arlene: To diagnose your cold-start noise we need to eliminate the possibility of any belt or belt-driven accessories as the noise source. Have the shop remove the belt before starting the engine on a cold morning. If the noise is still present, then the next step is to disconnect the power to the electric smog pump, if equipped. When checking for a vacuum leak a smoke machine and/or pouring water on the intake area is another way of looking for a vacuum leak.
Dear Doctor: Most cars equipped with automatic transmissions recommend changing the transmission fluid after 30,000 miles. What about CVT transmissions? I've gotten conflicting information about my 2005 Freestyle from two different Ford service departments. One said no need at all for a CVT fluid change, but the other said it was recommended after 60,000 miles. Any advice? Mike
Dear Mike: Continuously Variable Transmissions run at higher temperatures than conventional transmissions. You should check your vehicle's owner's manual for the manufacturer's recommendation -- not the dealer recommendation. You have to use the factory recommended fluid only -- and should not use any other fluid. If you use the vehicle for towing, commercial or snow plowing, then I recommend the transmission fluid should be changed annually. The main reason for transmission failure is heat and burnt fluid.
Dear Doctor: I just purchased a pre-owned 1996 Mercedes-Benz with approx 65,000 miles from a Honda dealer. The car ran fine for the first few days. What's been happening recently when I start the car is it cranks but will not start. It almost seems like it's not getting any fuel. When I wait five to 10 minutes the car will start up. Both mechanics at Mercedes-Benz and the Honda dealer have had the car for two weeks and cannot figure out what's causing the problem. Also the gas gauge is not working properly. The needle on the gauge seems to bounce up and down. Could these problems be related? Frank
Dear Frank: If I were working on this car the first thing I would do is a full-vehicle specific computer scan, followed by a scan in mode 6 operation. If there were no fault codes and nothing in mode 6, then I'd access my account at Identifix for a history of problems. A very common fault on these cars is the crankshaft position sensor. The fluctuating fuel gauge may not be at all connected, and again, a scan tool check will display the actual sending unit information that is going to the dash cluster. There is an ongoing internal dash cluster problem with these cars.
Dear Doctor: I have a 1999 Honda Accord V-6 with over 200,000 miles. Sometimes the car experiences hesitation. I have a P302 code misfire on cylinder #2. I changed all six spark plugs, the rotor, cap and wires. Also I tightened the intake manifold to manufacturer specifications. It erased the code, but it came back. The "check engine" light comes on in the morning and stays on. Once in a while it resets and goes away, but comes back on the next morning. Please help. Moshen
Dear Moshen: You need to find out when the misfire code appeared. This is done with the scan tool in a freeze-frame menu. You need to look at all of the sensor information to determine if this is a lean condition or mechanical problem. Much can be learned from scan tool information in the freeze-frame mode. Make sure you are using factory Honda tune-up parts.
Dear Doctor: I am looking to purchase a used Infiniti QX56. After doing a bit of research, there seems to be one potentially hazardous condition that is frequently mentioned: the brakes. The complaints seem to indicate a similar pattern of loss of braking, usually suddenly. What can be done to prevent braking problems with this vehicle? I love the vehicle, but don't love it enough to risk my family if it's unsafe. William
Dear William: As for any major braking issue, I would say there is reason to not consider the purchase the vehicle. However, if you would like to upgrade the brake pads and rotors, then there are many performance brands that will improve all-around braking. Beware that high-performance brake pads and rotors will have some occasional brake squeal (a small inconvenience for increased braking).
Junior Damato is an ASE-certified Master Technician.
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