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Q: I have a dedicated set of winter tires and rims that I use from November through April, then switch back to the set that came with my car. A local shop stores and installs my tires. Each time, they charge me for "tire balancing." I understand balancing when tires are placed on rims, but wonder if it is required for dedicated rims or if I am being charged for a service I don't need.

R.L., Mundelein, Ill.

A: This may be a CYA (cover your, mmm, butt) procedure so you don't come back complaining of a vibration. Although unlikely, it is possible one or more balancing weights may have come off during the transition. If you don't want the tires balanced, request that they don't do it. But be aware of the potential issues.

Q: Here's a new one. I took my Audi A3 in for its 10,000-mile checkup. The TPMS had been coming on, so I asked them to check it, since all four corners measured pretty much the same. They said the TPMS was fine but the tires were overinflated at 41 psi. They told me the number on the window sticker was a "Transportation Tire Pressure" figure for when the car is in transit to the dealer! Once in everyday use, the tires should be at 36 psi, which is what they reset them to. I've never heard of such a load of hooey. The factory needs to be reminded of the proper tire pressure but the owners don't? Ever hear of such a thing?

J.P., Winnetka, Ill.

A: Initially we speculated that overinflation would help prevent flat spots during shipping, but we turned to the technical experts at TireRack for backup reassurance. They confirmed that flat spotting is an issue, especially for cars that are shipped from overseas, spending much time in transit on a ship. The vehicles are also usually strapped down during transit. Before they are shipped to various dealerships, even domestic vehicles may spend plenty of time in regional holding lots. Finally, it is easier to let air out during the dealer's pre-delivery inspection (PDI) than to add it. The PDI guy needs to know. No hooey.

Q: I recently took my 2017 Corvette in for its second oil change (7,800 miles). Three days later I noticed a huge cloud of white smoke in my rearview mirror three times on that day. This has happened 11 times in the past month, all occurring at local speeds with slight accelerations. The dealer has had the car twice for a total of 15 days and reported that they could not duplicate the problem and told me to just keep driving the car until it becomes worse. GM simply advised me to listen to the dealer and closed the three cases that were opened. Any ideas?

P.M., Coral Springs, Fla.

A: As the weather grows cooler, even in Florida, steam may be seen puffing from the tailpipe. One of the emissions from combustion is water, in the form of vapor or steam. Since it is not an evil emission, there is no EPA issue. The worst-case scenario would be a blown head gasket, allowing engine coolant to enter the combustion chamber. By the way, if hydrogen-powered cars ever come to pass, their only emission is water vapor.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician.