Q: I own a 2019 Subaru Forester. It has a direct injection engine. DI appears almost unavoidable now. I am very happy with my new Forester but am wondering whether there is anything I can do to ward off the valve buildup that seems to be inherent with this design. I’m not sure whether automotive engineers have figured out how to prevent this issue.

I have read about folks installing “catch cans” in the PCV system to condense and trap oil and water vapor, theoretically preventing them from going back into the intake and causing buildup. What is your opinion of these devices? Would installing one create issues for me when I take the car in for service at the dealer (i.e. avoid claims that it violates warranty)?

I would like to avoid or at least delay the seemingly rather major job of pulling apart the intake side of the engine to clean and remove buildup every 60,000 miles or so.

— G.W., Chicago

A: If it were as simple as installing a catch can, don’t you think that the automobile engine engineers would have thought of it first? I would advise against it and, should engine damage occur, it might void your warranty. Pulling the cylinder head is a costly service, but I know of no shortcuts.

Q: I drive a stick shift. When parking, I usually leave it in neutral and just set the hand brake. In the winter, the brake often sticks and doesn’t release until I start driving. Would it be better to leave it in gear and park without setting the parking brake when it is cold out?

— M.C., Chicago

A: The sticking problem may be more pronounced when the weather is near freezing and the moisture on the rear brakes freezes. Although I would still set the brake, you can get away with putting the transmission in gear, as long as you are not on a hill.

I suggest using reverse. The gear for reverse usually has square cut gear teeth instead of the helical cut on the forward gears. As such, it is less likely to allow movement.

Q: I have always wondered what are the advantages of a passenger side rearview mirror that is so deceptive that a warning that “objects in mirror are closer than they appear” is on it. Have you ever had to merge to the right using it? If that mirror is so great, why aren’t all three rearview mirrors of this type?

— P.Y., Poquoson, Virginia

A: That mirror is for your safety. The right side of the vehicle has a much greater blind spot than the left. The convex mirror is designed to give the driver a wider view than can be provided by a flat mirror. Many motorcycles have convex mirrors on both sides because there is no center-mounted rearview mirror and together the left and right mirrors cover most of the area behind the bike.

Q: Thank you. We are grandparents in our 80s and appreciate your column each and every time we see it in the Sun Sentinel newspaper. We often make copies of it and send them to our children and grandchildren. The information you provide helps make life easier.

— E.W., Boynton Beach, Florida

A: As Thanksgiving is recently behind us, it is I who must thank my readers for their questions. Without you, I would be out of work.

Send questions along with name and town to Motormouth, Rides, Chicago Tribune, 160 N. Stetson Ave., Fourth Floor, Chicago, IL 60601 or motormouth.tribune