Car Talk

Q.

Is it technologically feasible to utilize a flat solar glass panel over (or as part of) a car roof in order to extend the driving range of battery-powered cars on sunny days? House roof solar panels are raised and angled to catch the sunlight, but this obviously would not work in an automotive situation because drag coefficient would be increased, thereby resulting in severely diminished economy. I seem to recall that a few years ago, Toyota used solar sunroofs to power an interior fan to ventilate hot interiors in some Prius models while they were parked. Could this technology be adapted in some way to recharge electric vehicle batteries so that driving range would be increased and dependency on plug-in recharging decreased in certain situations?

A.

Not until solar panels get a lot more efficient and cover a lot more of the car's surface area. They just can't produce enough power yet to make a meaningful difference.

You need to provide something like 36,000 watts to power a 50-horsepower electric motor (that's less than most electric car motors, by the way — the Chevy Bolt's motor, for example, produces up to 200 horsepower). A typical solar panel, on the other hand, produces about 300 watts.

So, if you were willing to park out in the desert for like 10 days, you might be able to fully charge up your EV with one panel. But by then your dashboard would be cracked and melted. Not to mention the Snickers bars in your glove box.

I mean, you're right that any extra power you add to the battery extends its range. It's just not clear, when you factor in the energy output and the cost of the panel, that it makes economic sense yet.

Pretty soon, car panels themselves — roofs, hoods, trunks — will be able to be coated with a solar collection film. That will multiply the potential collection area. And over time, solar collectors themselves will get more efficient and be able to produce more energy.

And if cars, and batteries, get lighter, that would help, too. So would autonomous cars, which could move around when "parked" to "catch the sun." Kind of like kids on spring break.

But we're not there yet. Write back to me in five years, and I'll update you on the progress.

Q.

I have a 2005 Pontiac Vibe with 63,000 miles on it. I bought it new and have had regular maintenance performed at the place of purchase. I recently took it in for an oil change, and was told that there is oil on top of the motor. They said the manifold needs to be replaced, for about $435. I took it to an independent garage that we have gone to for years, and they said it is the head gasket, and is about $1,500-$2,000 to repair. Why would this happen to my car? I am a 78-year-old woman who does not hot-rod her car. Who should I believe? It is not dripping oil on my garage floor. The mechanic at the independent garage said to keep an eye on the oil and add when needed. Help!

A.

I'd be tempted to take the advice of your independent mechanic, and just keep an eye on your oil level and top it up when necessary.

You don't say how often you've had to add oil so far. That's a key piece of information. If you have to add a quart every 1,500 miles, then there's no urgency at all, and you can just keep an eye on it — perhaps for years. If you're adding a quart every 500 miles, then some more investigation would make sense.

So start by monitoring your oil use. Have the guy at the independent shop show you how to check the oil. You'd do it in the morning, before you drive the car. Check it once a week and see how many miles you drive before it gets down to the "ADD" line on the dipstick (meaning you're down a quart).

If it is losing a quart in less than 500 miles, start by getting the engine steam-cleaned. Between the wind blowing in through the grille and the general grimy disgustingness of engines, it can be hard to tell exactly where a leak is originating. By cleaning the engine and then checking the area again a week or so later, it can be a lot easier to see what's actually leaking. If your mechanic has a dye system, he can put a special dye in the oil, and then look for the leak with a black light. If not, he can just do his best to trace it to its source.

If I had to take a wild guess, I would say the guy who suggested it's the head gasket is more likely to be right. We see a lot of leaky head gaskets on these cars.

I also like his advice to watch and wait. After all, at this age (the car's, not yours) there's no sense in doing anything rash, especially if your garage floor isn't even getting dirty yet.

Got a question about cars? Write to Ray in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at www.cartalk.com.