Get an expert to fix car’s air flow issues

Dear Doctor: We have a 2007 Mercury Grand Marquis. It has low mileage and is well maintained. Our blower motor works; we have air conditioning and plenty of coolant. But there is no heat. I’ve done my research and narrowed it down to the “blend door actuator,” which I see is a common problem. Is there a work-around without tearing apart the dashboard to restore heat? I also see that the passenger side airbag has to be taken into consideration, as to not deploy it while attempting to reach the actuator. Can you advise?

— Rick

Dear Rick: Blend door actuators are a common problem in many auto makes, not just Ford vehicles. In some cases the blend door can be accessed by removing the glove box, radio or just loosening all dash screws and pulling the dash back enough to access the actuator. I have also seen the actual blend door bind in the heater box, which can require complete heater box removal. Before leaving the car at an independent shop ask if they are familiar with the job needed and get an estimate, as well as an estimate from a Ford dealer. As for airbag deployment, once the battery is disconnected, I always recommend 30 minutes (to allow the capacitors to deplete their internal power) before disconnecting the airbag.

Dear Doctor: I have a unique opportunity to acquire a 2011 Toyota Camry with only 7,000 miles. The car is located in an underground parking garage. I need to know what to inspect before I start the engine and drive it out of the garage. How should I prepare the vehicle?

— Herbert

Dear Herbert: Congratulations on this rare find. Make sure the oil and coolant are at full levels and the tire pressures are set as recommended by Toyota. When you get the car to the shop have the technician change the oil filter, test the battery, and inspect for any cracking on the tires. There will be some tire shake from the flat spotting due to the tires sitting, but this should go away after 5 to 10 miles, or as soon as they get warm.

Dear Doctor: I recently relocated my 1995 Ford Mustang GT 5.0 to Virginia. I passed the New York State emissions test, but in Virginia my car failed based on high hydrocarbons. What problem caused this?

— Frank

Dear Frank: High levels of hydrocarbons are an indication of unburned fuel. There are many reasons including weak spark, too much fuel pressure, or ignition timing. You could even have a mechanical condition such as a weak valve. Find an ASE-certified technician in your area. You can contact a Ford dealership, AAA or Identifix for a list of locations.

Dear Doctor: My 2000 BMW 740 makes noise on both sides of the motor where the timing chain goes over the sprockets. There is 137,000 miles on the car and the check engine light is on. Are the timing chain rail guides causing this problem? Does the motor have to be removed to make these repairs? Is there any harm being done by starting the engine and driving a short distance just to keep the battery charged? George

Dear George: Your BMW has a very complex engine and it will be expensive to repair, very likely. If you go forward with repairs get a written estimate before any work is performed. Most shops will do major repairs like this with the engine while it is still in the car. I have also seen the engine removed to replace all the usual gaskets and plastic pipes, which also fail. Regarding the check engine light the computer needs to be scanned to see what the problem is. As long as the engine noise does not get louder you may be OK. But I would suggest you get an opinion from a professional technician in your area who works on BMW vehicles.

Dear Doctor: I read your column where you change your wife’s Toyota Camry V-6 oil every 2,500 miles with synthetic oil. When I purchase a new car I use conventional oil until 10,000 miles and then switch to synthetic oil for the remainder of ownership. I drive my vehicles over 15,000 miles annually. Since I’ve been using synthetic oil, I have increased the oil change interval to 5,000 miles. Should I lower the oil change intervals to 3,000 miles for engine longevity? Peter

Dear Peter: I accelerate oil change intervals because of my wife’s very short trips and limited driving. Today’s oil and engines are very much improved and do not require the frequency of change as in the old days. Indeed, 5,000-plus-mile change intervals are more the norm today. The most important thing to remember is to use the correct oil and viscosity that the auto manufacturer recommends. Full-synthetic oil has proven to be money well spent, as does a name brand oil filter.