Q. My wife’s 2007 Honda Civic was blowing hot air when the A/C was turned on. I purchased a 12-ounce can of R134a refrigerant and recharged the system. It is working fine right now. However, this car’s A/C was also recharged last year by my mechanic. How long should refrigerant normally last? I have never recharged my 2009 Volkswagen Jetta. I’m thinking there may be a leak in the Civic’s air-conditioning system. Your thoughts?

A. There was a time, many years ago, when recharging an air-conditioning system every few years was fairly common. Today, because systems are much better sealed, some vehicles — like your 17-year-old Volkswagen — may never need refrigerant added. If your Civic needed refrigerant again after only a year, there is likely a slow leak somewhere in the system. Topping off the refrigerant will usually restore cooling temporarily, but eventually the system will become low enough that performance drops off again. Keep in mind that adding refrigerant can temporarily restore cooling if the system is low, but overcharging can also damage the system. At that point, have the system professionally checked for leaks. Common sources include leaking hoses, O-ring seals, condensers or compressor shaft seals.

Q. I watch a lot of DIY videos and notice some people carry knives, multi-tools or mini pliers. What do you — or did you — keep in your pocket?

A. Although a bit geeky, for years I carried a pocket protector with a Phillips/flat-head combination screwdriver, flashlight, tire-pressure gauge and a decent-quality pen. Today, I usually carry a small pocketknife and keep a multi-tool nearby. Lately, it has been the TRUE Titanium Pocket Multi-Tool. For lighting, I replaced my old Streamlight with an OLight ArkPro Flashlight. It is compact, rechargeable and very bright. It also features a green laser pointer, which is handy for pointing out issues on cars without touching them, plus a UV light that can help track leaks when fluorescent dye is added to the system.

Q. Are gas additives to clean injectors necessary or recommended? I see lots of mixed answers. We have a 2024 Toyota RAV4 Hybrid that we really like and plan to keep for a long time, so I want to do right by it. If injector cleaners are worthwhile, what ingredient should I look for?

A. Based on testing I have seen over the years, using a fuel-injector cleaner periodically does make sense. In fact, some vehicle manufacturers now include injector-cleaning service as part of regular maintenance. For something like your Toyota hybrid, using a cleaner two or three times a year is reasonable. My preferred product is Chevron Techron because it contains polyetheramine (PEA), which is an effective combustion-chamber and injector cleaner. Using gasoline from stations listed at Top Tier Gasoline can also help keep injectors and combustion chambers cleaner over time.

Q. My car’s check-engine light is on. What should I do first?

A. Start with the basics and make sure the gas cap is tight. A loose or faulty gas cap is a common reason for a check-engine light. If the light is flashing, get the vehicle to a repair shop as soon as possible. A flashing check-engine light typically indicates an engine misfire that can quickly damage the catalytic converter. If the light is on steadily, have the computer scanned for diagnostic trouble codes. The code itself does not always identify the exact failed part, but it points a technician in the right direction. Some auto-parts stores will scan the codes free of charge and may even provide a basic AI-assisted diagnosis.

Q. About two or three months ago, my son received notice that his 2004 Dodge Ram pickup has a faulty airbag that needs to be replaced immediately. The notice said the truck is dangerous to drive and should be parked until repaired. My son has called the number on the recall notice several times and left messages, but no one has responded. He also contacted a dealer who said he would order the part and call back, but he heard nothing. The truck has only 60,000 miles, is in good condition and is registered and insured. It really needs to be back on the road.

A. This is especially frustrating when there is a “do not drive” warning and no one follows up. I would escalate the issue directly through Stellantis. The company has a dedicated number for “Stop-Drive” advisory notices: 833-585-0144. I would also contact multiple dealers instead of relying on just one. In addition, it would be worthwhile filing a complaint with the National Highway Traffic Safety Administration (NHTSA). This is a federally tracked safety issue, and the manufacturer is legally required to remedy the safety recall.

Q. I have a new Honda CR-V, and my neighbor has a small boat that I am interested in buying. The boat, motor and trailer weigh about 2,500 pounds. Can I tow it with my Honda?

A. Most Honda CR-Vs have a towing capacity of 1000-1,500 pounds. Your CR-V may be able to tow that amount of weight, but it exceeds the vehicle’s rated towing capacity and is not recommended. The concern is not just engine power. The bigger issues are the cooling system, transmission durability and, most importantly, braking capability. A CR-V can generally handle towing a Jet Ski, lightweight utility trailer or small camping trailer, but a 2,500-pound boat package is simply beyond what the vehicle was designed to tow safely.