Viewer-submitted questions for The Car Doctor:

Q: I am considering trading in my 2022 Corolla LE for a new Corolla Hybrid LE (you seemed to have liked it), mostly due to better gas mileage. Since my city driving miles are so low, I’m hoping to see a big improvement with a hybrid (and fill up less often).  Do you have any thoughts about the long-term maintenance costs of a hybrid car vs. non-hybrid, as well as general wear and tear over the years of those two types of cars? This could factor into my decision.

A: The Corolla hybrid is a great car, comfortable and fuel efficient.  Many drivers prefer conventional hybrids as well as plug-in hybrids (PHEV) over battery electric cars. This is especially true if you cannot charge at home, possibly because you live in an apartment, condominium or your current service will not support the additional electrical load. In my opinion, the maintenance costs between gas-powered and hybrids are about the same for the first 5-10 years. After 10 years, the hybrid battery comes into question. Before jumping to a hybrid, I would calculate the cost of the new car with the value of the trade of your used one. The last hybrid Corolla I drove was all-wheel drive and was close to $32,000, and a mid-level hybrid might be in the $26-$28,000 range. Your current Corolla has a solid value, but it will take many years of gas savings to make up for what could be a $4,000 – $6,000 difference in cost.

Q: I am buying a new Subaru Forrester and want to sell our 2017 Outback. My daughters suggested going through Carvana, CarMax, AutoNation, or another service to get a better price than the dealer is offering. We have never used that service and wanted your opinion. Is it safe, secure, and how do we get the money? Do you like some of the companies better than others?

A: I have known people who have used CarMax, Vroom and Carvana and it is a pretty simple process. The company will ask for several photos of the car and will either pay by check or do an electronic funds transfer. A year ago, I had someone who tried all the major companies and found CarMax offered the best price.  However, you need to take the car to a CarMax location; the others will come to you. These companies all use the same methods to estimate a price, so you will find the offers are very close. Keep in mind that when you trade to a dealer as part of a new car purchase, that trade will lower the new vehicle’s sales tax. Therefore, if the trade-in was worth $15,000 with Carvana but the dealer offered $14,000, the price would be the same since the trade-in would save you a little over $1,000 in taxes. Just something to consider as you do your research.  

Q: I own two Honda Accord EXL 4-door sedans, a 2013 and a 2018. The air conditioner in the 2013 model cools much more quickly in hot weather than the 2018 does. The condenser in the 2018 model was replaced under warranty after being punctured by a stone. Honda refilled the system to capacity and pressure. I did some snooping under the hood and discovered that the vehicles use different refrigerants (HFC-134a ((R-134a)) in the 2013 and R-1234yf in the 2018). Could the newer refrigerant be the cause? The newer car takes longer to cool off until it reaches the correct level of cooling. Thanks for your always informed answers.

A: The newer, safer refrigerants all have different characteristics. In older cars with Freon-R12 when people changed to R134a they found the same issue of longer cool times and slightly higher temperatures. Although factory air conditioner systems are optimized for the type of refrigerant, results still vary. Studies show that R1234yf system has a 5-25% lower cooling rate and, in many cases, uses a smaller compressor to helps save fuel. Depending on the vehicle, cooling may also be limited when the “ECO” mode is selected. There is likely nothing wrong with the air conditioner on your newer car, it’s just different.

Q: Have a 2021 Honda CRV with a sunroof. Recently, while the car was turned off and parked in my driveway, all four windows opened all the way and the sunroof also opened. I live on one of the approach paths to JFK airport. Could a passing aircraft have somehow triggered this action? I am concerned that this could happen while parked outside in a rain or snowstorm.

A: I have not heard of tower or jetliner communication interfering with a car’s electrical system. Some Honda vehicles do have a little-known function where if you push the lock button once, then unlock button twice and hold it then all the windows and sunroof open. Perhaps you mistakenly did this?

Q: I recently read about a device that you can put in your car that uses Electromagnetic Molecular Interference to keep snow and ice from building up on your car. The website looks impressive. What do you think?

A: I never heard of this, so I searched Electromagnetic Molecular Interference ice melter and based on what I read, it seems to be a scam. The website has poorly written copy with typos and not much history. There are lots of very scientific sounding principles but it also looks like a very similar solar powered air freshener. Let me put it this way: don’t spend your money on it.

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