Q: Being a very frugal person, I switched from 4/40 to air-conditioning years ago when I learned that driving with windows open ruins the aerodynamics of an automobile and reduces gas mileage dramatically. Plus, the noise with windows open is hard to live with. – M.H., Chicago
A: You confirm with what I said in this column a couple weeks ago.
Q: Your response about keeping the windows open may not save gas. My 2011 Honda Fit loses as much as 10% when I run the A/C. A Honda Fit only has about 125 HP so A/C drag is more significant for small cars. – R.A., Minneapolis
A: To every rule, there is an exception. I need to research this in greater detail.
Q: You recently wrote that Americans have a fetish for frequent oil changes. My 2013 Honda Civic has an oil quality sensor. Can I believe the reading? – C.W. Des Plaines, Ill.
A: Yes, you can. Carmakers, including Honda, do not want owners to have problems. The companies want them to buy another when the current one wears out or the owner gets tired of it. There are “over maintainers” amongst us who change their oil more frequently. There is nothing wrong with that if you have the time and money.
Q: My wife’s 2014 Accord has about 51,000 miles on it. I still do the basic stuff such as oil and filter changes, wiper blade replacement, and keeping the tires at the correct air pressure. Other stuff goes to the pros. I realize that the maintenance minder uses algorithms for oil change intervals and probably coolant change intervals. How does the minder determine other functions such as replace/check brakes, change transmission fluid, etc.? Is it mileage, sensors or voodoo? Love your column for the info and humor, first place I go to every Sunday, even before Dilbert. – A.L., Tinley Park, Ill.
A: The items you ticked off are not voodoo, they are you do. You do the task whenever it needs to be done. Since it is up to you, the carmaker has provided help in the form of a book that spends most of its life in the glove compartment … unopened. I love Dilbert.
Q: A friend of mine just bought a 2002 Corvette. Nice car but he neglected to check out the lug nuts. The wheels have a locking lug nut on each one. There is no master unlock and previous owner is not answering his calls. Any idea on how to go about getting them off without wrecking things? – J. F., Chicago
A: There are ways to remove the locking nuts. Many professional technicians know how to do it. Of course, they will be damaged beyond repair so your friend will have to buy a new set of locking nuts that will include the proper key. The other option is to take his chances with standard lug nuts.
Q: As regards J.F. in Chicago with the locking lug nuts on his 2002 Corvette; I would suggest that he take his car to a Chevrolet dealership. If the locking lug nuts were installed when the car was originally purchased, a dealership might have a master socket. When I take our Honda to my Honda dealership for tire rotation, they don’t need my unlock socket, as they have a master socket. – E.L., Allentown, Pa.
A: Good point and something I had overlooked.
Q: Regarding jake brakes, they are designed for the retardation of vehicle speed when on a down grade. There is no reason, other than to save regular brake linings, for their use if there is no danger of the vehicle over-revving and the driver losing control of the vehicle. They are remarkable safety accessories when used as designed. The use of engine retarders on the flat is the sign of a lazy, cheap, non-maintenance focused, driver. Pick one or all of the above. It’s like the driver who uses the trailer brakes to stop the vehicle. In many cases, the trailer belongs to someone else. Unfortunately, not many traffic enforcement vehicles come with audio monitors, and the duration of use is short. – B.S., Lincolnshire, Ill.
A: In town or a residential area, they are also a source of noise pollution.
Q: For reference, a muffler was developed to quiet jake brakes. It was offered with a guarantee to pay any tickets resulting from using jake brakes in no engine braking zones. The truckers were generally not interested. They enjoy the engine brake noise much like the Harley riders like their unique sound. – D.G., St Paul, Minn.
A: I hear you.
Q: I drive a 2017 Acura MDX and the owner’s manual specifies that 91 octane fuel is “recommended.” The sales staff tells me that mid-grade (89 octane) or even regular grade (87 octane) is acceptable. I’ve used mid-grade for two years and the engine and performance are good. How does the engine determine the octane level and how does it internally adjust to fuel that is lower than the recommended grade? – K.K., Schaumburg, Ill.
A: With spirited driving, engine knock can occur, so the preferred fuel is one with a higher octane. Under less spirited driving, engine knock is less likely, so mid-grade or regular gas is fine. Continued engine knocking will cause damage, so a knock sensor screwed onto the engine reports the first signs of knock to the engine control module that then backs off the ignition timing until the knocking stops.
Q: We have a 2010 Toyota Highlander with 58,000 miles. On my last couple visits to the dealer for routine maintenance, they have recommended an engine de-sludge. We have kept up with oil changes and other maintenance at the recommended intervals. Is this something modern vehicles need or are they just trying to get me for another $170? – S. M., Skokie, Ill.
A: They are de-sludging your wallet. Select this service if your bulging billfold is bothering you.
Q: Would I be creating a problem with over-heating the engine or something else under the hood by covering the hood of my Ford Escape with towels, so a cat doesn’t scratch the paint? When I arrive and the car is hot, I am covering it up and it stays hot for hours. – D.G., South Daytona, Fla.
A: The temperature under the hood will be it highest when you turn off the engine. It gradually cools down (called hot soak in the industry) and all you are doing is stretching out the hot soak period.
Q: I have a Porsche Panamera with SiriusXM, and the exact same thing happened to me. Apparently, Sirius sent out an update that Porsche’s PCM and the whole system would continually reboot every 2-5 minutes. The solution to this is a procedure Porsche calls a “handover.” They use this when a car is sold, traded in, etc., and want to wipe all info from the system. Just google Porsche handover and follow the steps. Warning: All your settings, tuner presets and such will be wiped out, so I suggest taking a picture of each screen before doing this. When completed, then request a refresh signal from Sirius. Back in business then. – P.C., Naperville, Ill.
A: I checked out the YouTube video recorded by a spokesman from Capital Porsche in Tallahassee. The procedure took him only a couple minutes, but as you stated, the owner will lose everything that was ever saved.
Q: As a kid I remember that when I was in junior high, we always had air conditioning in our car, but my dad would never use it, saying it killed the gas mileage. He believed in 4/40 A/C. Now I never hesitate to turn on the A/C and I don’t seem to see a lot of gas mileage difference. Do the electronics in today’s cars really compensate the gas usage when the A/C is on? – R.F., Warrenville, Ill.
A: Ah yes, the 4/40—four windows down at 40 miles per hour. It was the poor man’s air conditioning for cars that did not have the system. Early automotive A/C was indeed a power hog. Compressors were large and clunky. Terribly inefficient. Automotive systems have come a long way becoming highly efficient. The electronics in a car are not really a factor.
Q: The maintenance manual for my 2016 MB 450 GLE Coupe says replace the spark plugs at 5 years/50,000 miles. But at my four-year service the dealer said 4 years/40,000 based on the MB 2016 Service Sheet. Customer Service says it’s a typo in the manual, which I question. – F.G., Libertyville, Ill.
A: You would be surprised how many dealerships print up their own service guides. All they need is some imagination, a computer and printer to make them look professional. Some service departments go as far as to post their service intervals boldly on the wall.
Q: I don’t understand how a fuel filter can be considered a lifetime part. I have a 4WD, 2003 Tacoma with 162,000 miles and when I asked the dealership about replacing it, I was told it does not need to be replaced. Nearly every other filter, like air and oil, are changed routinely so why not fuel? – C.M., Quakertown, Pa.
A: There is a filter on the fuel pump pickup pipe. Often called a sock, it protects the pump and everything beyond. Gasoline is much cleaner nowadays and gasoline dispensers have filters in them. I have seen cars go hundreds of thousands of miles without a fuel filter replacement.
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