If you want to upgrade your 6-volt battery, think bigger

Dear Car Talk:I have a restored 1947 Plymouth Business Coupe. That was the same year I, too, came off the “assembly line.”

The Plymouth has a 6-volt battery, and the starter motor turns over slowly. Can I safely install an 8-volt battery?

Will this improve my starter motor? Or, will this risk damage to my lights and instruments? Thank you. — Jerry

All of the above, Jerry. The problem is that everything in your car is designed to run on 6-volts.

Running 8-volts through 6-volt components will put some stress on them and might shorten their lives a bit. But in truth, the lights and instruments can probably handle an extra two volts. It’s not enough extra voltage to cook them.

The bigger problem is that you have a 6-volt generator. And, a 6-volt generator will never be able to charge an 8-volt battery. So, your idea will work for about two hours.

And, you can’t simply replace the 6-volt generator with an 8-volt generator in this car, because they don’t make an 8-volt generator.

Your best option is to skip over 8-volts entirely and just jump right to 12-volts. You’ll basically convert the whole car to a 12-volt system. There are kits for this. Other old-rustbucket enthusiasts can advise you.

You’ll need a kit that has 12-volt bulbs, a 12-volt windshield wiper motor, a 12-volt generator, a 12-volt starter motor, a 12-volt voltage regulator, etc. And you’ll probably need to replace at least some of the wiring. Fortunately, a 1947 car only had about seven wires, so that’s not a big deal.

So, 12-volts is the way to go, Jerry. That’ll solve your starter motor’s chronic fatigue syndrome and any other electrical problems you have. It’ll also solve that problem of figuring out what to do with your next 12 weekends.

Dear Car Talk: My 2011 Hyundai Elantra Touring with 145,000 miles is making noise. It’s making an intermittent, lowpitched squealing (more like moaning) sound when the car is moving and only when it’s moving.

It’s not a belt, because I can race the engine in Neutral and it never happens. The sound happens after I’ve been driving for at least 5 minutes, and it varies with speed between the moan, a hum and squeak, but it’s always intermittent.

It comes from the front of the car. It stops when the car stops and may or may not start again when the car starts moving again. My best guess is wheel bearings. What do you think? Thanks. — Judy

I don’t think it’s a wheel bearing, Judy. Wheel bearings make a gravelly noise, like a cement mixer. And, they’re unlikely to come and go. Once a wheel bearing is bad, it’ll make noise all the time.

That’s good news, because bad wheel bearings lead to wheels falling off. So driving with a bad wheel bearing is not something I recommend.

I think you have a sticky brake caliper. The caliper squeezes the brake pads together around the wheel’s brake rotor when you step on the brake pedal. Then, once your foot comes off the pedal, the caliper is supposed to release, pulling the pads back with it, and allowing the wheel to turn freely.

But sometimes, older calipers stop releasing. Or, they release too slowly. Or, release sometimes and don’t release other times. And I think that’s what’s happening on your car.

Sticky calipers tend to act up after you use the brakes a few times — which would explain why the noise starts after 5 minutes of driving.

Depending on how tightly the caliper is still squeezing, the noise can vary, from a highpitched chirp or squeal, to a rubbing, groaning noise.

And, it would be intermittent. It could be affected by how hard you apply the brakes, the weather and what exact position the caliper is in at any given moment.

So, I’d ask your mechanic to check your calipers. My guess is you’ll need at least one front caliper replaced.