A good tire technician will identify the leak, clean the rim and seal the tire

Q: I purchased a 2009 Toyota Camry in July of 2015. At the time, the car had 103,000 miles on it and the tires were replaced just before I took possession of the car.

Now the car has 117,000 miles on it and every six weeks the low tire light comes on. When I take it to the local shop, three out of four tires need about four pounds of air.

My driving is local, but the low tire light makes me nervous. What should I do?

A: The tire is most likely leaking from the valve stem, around the rim or even around where the wheel weights are installed that are used to balance the tires. A good tire technician will identify the leak, clean the rim and seal the tire with a commercial tire bead sealer and that should solve the problem.

Q: I have 2000 Volkswagen Jetta VR6 that I love, and it is closing in on 300,000 miles. I would like to keep it until it reaches 500,000 miles. The problem is when I use the air conditioner, there is a lot of heat that comes up through the floor at the shifter and under the dash.

The Volkswagen dealer and my local repair shop have looked at the car and can’t find anything wrong.

I want to keep my car running at 100 percent, but I’m not happy with this issue. Do you have any ideas?

A: When the air conditioner is on, it is not unusual that the engine and exhaust may run a bit hotter. All cars have some sort of heat shield to insulate the exhaust from the body of the car. Your Volkswagen uses an insulated heat shield that is mounted to the body.

It is possible that the shield has been damaged from road debris or even removed when a mechanic was working on the car. If the shield looks OK, then the next step would be to take some temperature measurements with the air conditioner on and off and see if the catalytic convertor temperature changes dramatically.

Q: I have a 2005 Toyota Camry with a 178,000-miles on it. The car runs great, gets good fuel mileage but puffs a little gray/blue smoke when I first start it. I assume this is an omen of bad things to come with the engine.

The car doesn’t drip any oil on the garage floor and doesn’t consume much oil between oil changes.

I’m not sure it makes sense to fix a car with these many miles, but I also don’t like the hassle or expense of buying a new car. Any advice?

A: The blue/gray smoke on start up is a classic sign of worn valve seals or worn valve guides. There are two methods to replace the valve seals. The most expensive and time consuming involves removing the cylinder head(s), depending on the engine this could take two days’ worth of labor.

The second method uses a specialty tool that allows a technician to remove the valve springs and replace the valve seals without removing the cylinder head. This method takes about half the time. Even though the car is 13 years old — if overall it is in good shape — it makes sense to fix it.

Q: I own a 2015 GMC Sierra 1500 double-cab 4x4 all-terrain with the Z-71 suspension and the 5.3-liter engine. I purchased this truck new and it now has 19,000 miles on it.

I don’t drive off road or tow anything, just commute and trips to the home improvement center.

I’m thinking of trading it for a 2019 Tacoma SR5 with the 2.7-liter V-6 engine. The model I’m looking at is four-wheel-drive with the access-cab.

What are your thoughts on which vehicle will go longer in age and miles with least problems. I have done lots of reading and the 5.3-liter engine has some questionable longevity.

A: When I was at a GM engine plant, the engineers told me GM products are tested to 175,000 miles. Based on my experience i would think your truck should get there with regular maintenance.

The Toyota Tacoma is one of the most overall reliable vehicles on the road and if it fits your lifestyle and budget it may be the way to go.

— John Paul is the AAA Northeast Car Doctor. He has more than 30 years of experience in the automobile industry and is an ASE-Certified Master Technician. Write to John Paul, The Car Doctor, at 110 Royal Little Drive, Providence RI 02904. Or email jpaul@aaanortheast.com and put "Car Doctor" in the subject field. At 8:30 Saturday mornings, tune in to John Paul, The Car Doctor, at wrolradio.com. Follow him on Twitter @johnfpaul or on Facebook.