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Q: My first turbocharged vehicle was a 2003 Volvo XC90 with a five-cylinder engine. The owner's manual stated that the engine should be warmed up to allow the turbocharger to come to temperature before driving and let the turbo cool down for a couple minutes before shutting the engine off.

I now have a 2015 Audi A5 with a turbocharged four-cylinder engine. The "nanny" reminder system tells me to "Avoid warming up engine while stationary." What do you recommend? Does a car's turbocharger need to warm up/cool down or not?

A: "There goes another guy with a blown turbo" was something we used to hear a lot when turbochargers debuted as a quick answer for more power from dinky engines. Blue smoke enshrouded cars as they burned oil. To help the turbo survive, motorists were cautioned to start and idle for about 30 seconds and to also allow the engine to idle for a minute or so before shutdown. The cooling-off period helped prevent oil from cooking in the hot turbo. Turbos have come a long way since then. Drive gently for the first five minutes and kill the engine normally unless you just pulled off the Autobahn.

Smart move

Q: I have a 2011 Ford F150 that frequently sits in our driveway without running. It has a 12-volt power outlet on the dash (not the cigarette lighter). It appears from testing that it is power-on capable all the time. Do you think a solar charger plugged in here would provide a trickle charge to the battery? I am concerned about overcharging the battery. My Ford service writer does not have the answer. I'm hoping you can help.

A: Solar chargers with overcharge protection (smart chargers) are the way to go. Check out your favorite auto parts store, big box store or shop online.

Back to the '80s?

Q: A recent question about whether you get better fuel efficiency the faster you go reminded me of an incident I experienced. I was on my way to a family gathering on an interstate with a 70 mile per hour speed limit when I encountered my sister on the same highway, heading for the same place. I was tooling along at 55, but she was flying at 75. Just for kicks, I decided to follow her. Normally, I could make the round trip on a tank of gas with enough gas left over for a couple days' worth for errands. Guess what? I was not even able to make it back on that tank of gas. I had to stop to refuel about 30 miles from home.

A: With the price of gas hitting eye-popping levels, we may see the return of the lower speed limits of the 1980s once again, but probably not anytime soon. But you prove the point that 55 vs. 70 makes a big difference.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician. His writing has appeared in automotive trade publications, Consumer Guide and Consumers Digest. Send automotive questions along with name and town to