Viewer-submitted questions for The Car Doctor:

Q: I own two cars with CVTs (continually variable transmissions). One is a 2011 Nissan Maxima bought used, “off lease,” from an independent car dealer; the second is a 2017 Honda CR-V (1.5L 4cyl., Touring model, bought new from a Honda dealer).  I have read that CVTs only last half as long as traditional transmissions.  The Maxima is nearing 100,000 miles, where (supposedly) CVTs can start to exhibit warning signs of failure. I would like to know what your professional opinion is on CVTs in general, what I should be aware of with these two types of CVTs, and finally what kind of preventive maintenance I should be doing to keep the CVTs happy and fully functional.

A: I’m a fan of gears, but that may be a generational thing. My experience has been that the earlier CVT were an issue on the car’s life, but the newer units are much better. I have seen the Nissan CVTs last several hundred thousand miles – but also as little as 50,000 miles. With normal driving, the fluid doesn’t have a required change interval. If you tow a trailer or drive more aggressively, you should change the fluid every 60k miles and use only Nissan fluid.  For the Honda CR-V, let the maintenance minder tell you when the fluid needs changing. As good as Honda vehicles are, their automatic transmissions were problematic in earlier years and, in my opinion, that’s why they may have switched to the CVT or the 9/10 speed conventional automatic transmissions in the larger vehicles.  Note, a failing CVT will hesitate, shake and vibrate and is quite sensitive to low fluid level issues. Any transmission leaks should be repaired as soon as possible.

Q: I recently read about one of your readers with odd electrical issues and thought I would share mine. My 2016 Audi S4 does occasionally react oddly when passing under the toll gantry at the lower level of the George Washington Bridge. Crossing under the gantry causes my windshield wipers to sweep across the windshield once or twice. I take the bridge on my way home from work, so this is a trip I take often. I am nonplussed by the fact that this doesn’t happen every time I make the trip but have no idea why it happens at all. I consider it to be another one of life’s lesser mysteries.

A: This is referred to as a “phantom wipe” and it is common in many vehicles of all manufacturers. And like many of life’s mysteries, this one does not seem to have an answer. If it truly bothers you, you can change the wipers from Auto to Off.

Q: I recently watched the move, A Man Called Otto, and there was a Chevrolet electric pickup truck in the movie. The truck doesn’t really exist and certainly not in that time frame. How does that happen?

A: Many vehicle manufacturers will use product placement in movies and television. What you saw was an early preproduction model of the all-electric Silverado. Automakers work with production companies to tease new models and gauge reactions. Other examples include the Audi E-Tron in the Ironman movie, or the Fisker Ocean that made a cameo appearance in the TV series The Lincoln Lawyer.

Q: My 2011 Honda Accord with only 83,500 miles has leaks in the power steering return line. I was told that the whole front carriage would have to be “dropped” in order to reach these hoses. All maintenance has been performed at this dealership, but this type of repair is radical at more than $2,500 since the dealer also wants to replace the entire steering gear.  I don’t know if I can trust that the frame will be safe to drive if the carriage is dropped and reinstalled. Honda explained these leaks can occur because the car is 12 years old. Is it necessary to “drop the front carriage” or could a solution to stop the leak fix the issue? Will the car be safe to drive after the carriage is reinstalled by the mechanics as opposed to the manufacturer?

A: I think it is time for a second opinion. If the issue is just the power steering line(s) are leaking, then they can be replaced without removing/lowering the subframe. If the steering gear is leaking, then the subframe needs to be lowered to gain access. This is a common repair procedure and completely safe.

Q: Could you please discuss run-flat tires?  I have a 2024 NX 350 Lexus that is equipped with them. I think many readers would appreciate learning about this as I believe many new cars have or will have them.

A: Run flat tires are exactly what they sound like. You can drive for a limited distance (50 miles at speeds no greater than 50 mph) with no air due to the very stiff sidewall. There come with a couple of issues: they tend to ride hard and may not be repairable (that varies by manufacturer). Years back when evaluating a new vehicle, I could tell which cars had run-flat tires due to the stiff ride. Today the ride has improved but is still very firm. If flat-run tires are on a sports car or all-wheel drive vehicle, you may end up replacing at least two – or maybe even four – due to one unrepairable run-flat tire, so cost is a factor. Call me old-fashioned but I like a spare tire, any kind of a spare tire!

Q: I am planning to buy a 2022 certified pre-owned Infiniti Q50 with 9,300 miles on it. Looking at the Carfax report, it appears the powertrain control module was replaced at 8,500 miles, and also replaced the coolant temperature sensor and the rear brakes. Given the car’s age and low milage, are these “red flags”?

A: I looked and there is no common problem with that module. However, my concern is that whatever prompted the change didn’t fix the core problem; that may be why the car was traded in so soon after the repair. That car uses a low- and high-speed communications network and there have been several bulletins about the CAN network and repair strategies. It may be a good car to buy, but it’s hard to say without knowing the complete repair history. My inclination is to keep looking.

Do you have a car question? Email the Car Doctor for a personal reply.

If you’d like more information, head to AAA Northeast.