Q: I have a 2016 BMW 528i. The fan motor is very, very loud. BMW tells me they have had problems with some of the 5 Series fan motors. Since this noise doesn't come up on an error code they won't fix it. Now when my car is idling in warm weather it sounds like a junk car. I am thinking of just getting rid of the car. Shame on BMW for knowing about this problem, but refusing to address it.
R.M., Chicago
A: This sounds like your fan might be running at maximum speed in an attempt to prevent overheating. If your coolant temperature is normal, there may be a problem somewhere in the cooling system giving the control module bad info. It could be a coolant temperature sensor, a water pump sensor, air conditioning command for more airflow or even a failing water pump. Leave diagnosis to a trained professional technician.
Q: My 2002 Dodge Caravan has trouble starting, mostly after the car has been standing overnight. It may require two more attempts until it starts the motor. I'm being told I need a new starter motor, which is expensive for the part and for the installation. I have been willing to put up with this difficulty, especially when it only shows up on the first start of the day. Someone advised me to tap on the starter motor with a heavy tool and it works. I have put up with this for several months now and though it is annoying, I can live with this as long as it does not get worse. Are there any fixes other than a complete replacement of the starter motor?
S.W., Morton Grove, Ill.
A: There are no fixes other than replacement. When the starter motor stops spinning, it comes to rest on a dead spot on the armature. Rapping on the starter nudges it just enough from that position. Eventually, you will either tire of whacking the starter (winter is approaching, ugh) or the starter will quit responding to your persuasion.
Q: In your recent response about bleeding tire pressure you recommended starting the day of a trip to the inflation pressure on the door placard. What about the situation where you are traveling across the country from the Midwest to the Southwest in the winter? On a recent trip to Scottsdale, Ariz., from Chicago my tire pressure went way up in warmer temperatures. Does it make sense, if you don't have access to an air compressor, to inflate your tires a bit more than the inflation placard in the evening and then recheck and bleed if necessary the next morning before driving the car?
J.C., Chicago
A: Tire pressure increases or decreases by about 1 pound per square inch for every 10 degrees of change in the ambient temperature. That is why it is important to make adjustments from season to season, or in your case, from latitude to latitude. Tire pressure should be checked and adjusted when the tires are cold, after the car has been sitting overnight or several hours. It is OK to drive about 5 miles or so to the nearest station if you don't have an inflator.
Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician.
