Q: Last fall I purchased a new 2016 Ford F-150 Lariat pickup with all the upgrades. The night before a planned trip, the temperature was minus-34 degrees so I plugged in the block heater. My pickup started in the morning but the heater inside the cab would only blow cold air. I contacted the dealer and told them what had happened. I was told by several staffers there that the heat inside the cab didn't work because I should not have plugged in the block heater until about two hours before we planned to drive it. I would have had to set an alarm for 4 a.m. so I could plug it in to leave by 6 a.m. It's hard for me to believe that. I'm a retired farmer and have driven vehicles with block heaters for decades. Not once have I gotten up in the middle of the night to plug in a block heater. Can you offer some insight and guidance?

D.S., Waconia, Minn.

A: Their response sounds ridiculous. According to the owner's manual for your truck, the block heater "achieves maximum temperature after approximately three hours of operation. Using the heater longer than three hours does not improve system performance and unnecessarily uses electricity." There is no mention of activating the heater only two hours before driving. The engine heater warms the engine coolant, which in turn heats the cabin. There is another problem, but we can't guess at what it may be.

Q: I own a 2013 Hyundai Sonata, 2.0-liter turbo. It has low-profile 225/45R18 tires. I find that these tires pick up every little bump, pebble, expansion joint or whatever on the road. It feels like I'm driving on solid tires. I recently needed to purchase new tires and asked for 225/55-R18, a tire that would be slightly higher and allow more cushion between the vehicle and the road. The tire store guys stated they could only mount tires that were listed on the manufacturer's plate on the vehicle. What is your opinion?

C.M., Cooper City, Fla.

A: Many stores limit their liability by only fitting the tire size, load index and speed rating shown on the vehicle door placard. This assures that tires with insufficient load capacity or speed rating don't get installed. According to an authority at Tire Rack, the taller tires change the overall diameter from 25.9 inches to 26.8 inches, which is 3.4 percent taller. The normal limit for variance in diameter is 3 percent, as speedometer, odometer, gear ratios, etc. are directly affected by changing the diameter. The increase also may cause rubbing during some situations, such as tight turns, especially over a bump. One option is to stick with the proper size, but select a softer-riding tire from the touring, instead of sport, category.

Q: Like a previous reader, I also had a Ford Explorer with a fuel gauge needle that stuck. My service adviser also talked about removing the fuel tank, etc., which would be expensive. But then he said to try Chevron Techron additive first. I poured a bottle into the fuel tank and it worked like a champ. No problems since.

C.M., Hawthorn Woods, Ill.

A: You are not our only reader to submit this idea; others also have said it worked for them. Thanks. We will pass it along and keep the tip in mind.

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. His writing also appears in automotive trade publications, Consumer Guide and Consumers Digest Send automotive questions along with name and town to motormouth.tribverizon.net.