Takes some sleuthing to find source of leaky tires

by Jim KerrBackyard Mechanic . Feb 02 2018

Question: I am being driven crazy by recurring slow leaks in my car’s tires. I drive a 2010 Civic EX-L that hasn’t cost me much in repairs, except for this tire issue. Is there some permanent fix for leaks like this? The garage thinks it is the alloy wheels corroding and they just sand the rim and that is it. But the tires soon start leaking again anyway. No evidence of screws/nails in most cases.

— Michael

Answer: The rubber in tires gets hard as it ages and this can make it more difficult to achieve a seal on the wheel if it is dismounted — such as could occur if you change to winter tires, but use only one set of rims. Also, the bead area of the tire is very easy to damage, especially on older tires, when they are dismounted from the wheel.

Even the most careful and skilled technician occasionally will damage a bead on an older tire. If the damage is bad enough, the tire may have to be replaced.

In your situation, it is suggested there is a leak at the bead area. Sanding the wheel along the bead area will help, but, if it’s rough due to corrosion, or there are some small rough areas on the tire bead, then a bead sealer chemical can be used to fill the small voids and stop leaks. Bead sealer is a liquid rubber that is painted on the bead area of the wheel before the tire is inflated and it is available from a local tire-repair supplies dealer. I am surprised the garage has not already tried this.

It is possible the leak could be in another area. I have seen alloy wheels that were porous. This can be repaired by sealing the porous area with some epoxy glue. The valve stem, or the valve core inside the valve stem, could also be leaking, so replace them when the bead sealer is applied. Immersing the inflated tire in a water container and looking for air bubbles takes time, but is a good way to pinpoint a small air leak.

Question: I have a Honda Accord that is a few years old. This winter, the battery needed replacing, so I put a new one in. During the last few days, the car has been hard to start and barely cranks over. The charging system checked OK, but the battery was almost dead. We charged the battery, but I am worried that it may not start again one of these days. Any suggestions?

— Don

Answer: Even a good battery can become discharged if weather and driving conditions work against it.

For example, when the temperatures get down in the -20 C range, a battery works like it is only about half its size. When temperatures reach - 40 C, the battery will act like it is about 25 per cent of its size. This is due to the slower chemical reactions in the battery when it is cold.

Cold also affects how a battery charges. At -40 C, it can take half an hour of charging just to warm the battery before it actually starts to take a charge. At -20 C, you may need 10 minutes of vehicle run time before the battery starts to charge.

At the same time, many drivers only drive a few minutes to work or between stops. Every time you crank the engine over to start it, you are taking 100 to 200 amps from the battery.

The headlights, heater motor, engine ignition system and fuel system can use 30 amps. Then you turn on the rear window defogger, which can use more than the headlamps. From there, you adjust the power seat and turn on the seat heaters. Oops, I forgot you wanted some tunes, too! All these power accessories can add up, so the vehicle charging system has very little extra to recharge the battery and what is left is initially used just to warm the battery. Short-trip driving with lots of restarts eventually drains the battery to the point it won’t start the engine anymore.

There are solutions. Combine trips so there are less starts. Turn off accessories when not needed. Keep the battery warm by either installing a battery blanket heater around the battery, or a small trickle charger onto the battery.

Or plug the block heater in when the vehicle is parked overnight.