Rev it up after starting?
Q: I seem to recall being told many times that one should not rev the engine when first starting it because the oil has not yet reached all the components (or something like that). If that is true, why do engines idle so high when you first start the car? Taping the accelerator pedal doesn’t seem to drop the idle speed. Bowing to your wisdom. — A.A., Bethlehem, Pennsylvania A:
During cold soak (the industry term for sitting for a while), a little bit of oil slips away from components, but not enough to result in damage when starting. A cold engine needs extra fuel because the gasoline doesn’t vaporize easily. In olden days, the choke limited the air, resulting in a richer fuel mixture, and you could tap the gas pedal to release the choke and the high idle. Fuel injection maintains the proper amount of gas and engine speed.
Q: I have a 2 0 2 1 Subaru Outback and the headlights are aimed too high. The dealership says they cannot be adjusted. Isn’t
this a safety hazard to the oncoming driver as well as to me from road rage? — J.B., Tully, New York A:
This is a somewhat common complaint. I believe the headlights can be adjusted. All you or your auto tech need is a super long Phillips screwdriver.
Q: I have a 2 0 1 0 Ford Fusion Sport. Love it. The tire pressure sensor fault message comes up on the dash. It has done this before then magically gone away. Recently put on a new set of tires and although not immediately, the fault message is back. My mechanic says they can hook up a device that can find a fault but somehow if a fault is found on one it can incorrectly give a fault reading on others. So, would it be best just to buy a set of new sensors and replace all instead of finding possibly only one faulty sensor?
— D.W., Virginia Beach, Virginia
A: The TPMS (tire pressure monitoring system) sensors for your car come as a 4-pack, which costs about $50. Get them all and get peace of mind.
Q: I recently had the oil changed in my 2 0 1 9 Hyundai Elantra GT and when I left the dealer’s service area, I noticed a louder than normal “grumbling” from the engine as I accelerated from a stop to 2 5 or 3 0 mph. The sound seemed to stop at that point. I love the Elantra, but it’s not the quietest ride I’ve ever had, so I didn’t think much of it. This continued for a couple weeks before I decided to go back to the dealer to have it checked out. After about 1 5 minutes, the service manager came out and told me that the “air box” had been left open, I assume during the oil change. He said that they closed it and that it wouldn’t have caused any problems. Sure enough, as I drove away, the grumbling noise was gone. I had never heard of an air box. Is it a real thing? Is it OK to drive when it’s open? — R.K., Michigan City, Indiana
A: The air box houses the air filter. It is OK to drive with it open for a while, but not all the time. Your engine doesn’t like sucking in dirt. Since the air filter sits beneath the cover, it has been doing its job without its lid.
Bob Weber is a writer and mechanic who became an ASE-certified Master Automobile Technician in 1976. He maintains this status by seeking certification every five years. Weber’s work appears in professional trade magazines and other consumer publications. Send questions along with name and town to motor mouth.tribune@gmail.com.