•Q. OK, I know this is a pretty ridiculous question, but I’ve done a little research and can’t find anything written on the subject. I was wondering if it’s possible to implement a sort of pull-start system (like a lawnmower has) on my truck. The reason I would want this is for a situation such as a dead battery with no one to give me a jump-start. I just figured that it would be nice to have a system like this for occasional use. Now, I know I can just buy a portable jump-starter and keep that in my truck, but is a modification such as this possible? I appreciate your time and help.•

RAY: Sure. On almost every car, there’s a big, fat nut on the crankshaft pulley that bolts to the front of the crankshaft. That’s the pulley with the serpentine belt running around it. If you were to turn that nut, you’d be turning the crankshaft and thereby “cranking the car.”

TOM: In fact, on old cars like the Model T Fords, that’s exactly what people did. They went to the front of the car, fit a wrench on that nut and “cranked it” until the engine started.

RAY: But it’s not so easy with modern cars. First of all, you don’t have easy access to it. Most modern engines are mounted transversely (aka installed sideways). So you’d have to smash a hole in one of your front fenders to get at the crankshaft pulley with a crank handle.

TOM: And even on a truck with a longitudinally mounted engine, like yours, you’d still have to blast a hole through the radiator.

RAY: But more importantly, it’s not easy to crank a modern engine. By comparison, Model T engines were tiny. You simply wouldn’t be strong enough to turn over a modern, high-compression engine by hand – even with the mechanical advantage of a pull starter or a wrench.

TOM: Think about it: Even a tiny lawnmower engine takes some effort to pull-start, and lawnmowers typically have 0.15-liter engines, as compared with the 2.0- to 3.0-liter engines found in typical cars. Or 4.0-, 5.0- and 6.0-liter engines in trucks!

RAY: So, a pull start is out of the question. But if you still want to pursue this idea, I guess you could employ some sort of separate electric motor to help you turn the crankshaft. Actually, we have those. They’re called starter motors! Your car already has one.

TOM: I suppose you could buy yourself a powerful electric drill instead – something that delivers, say, 5 horsepower (the starter motor, for comparison, delivers 8-10 hp). But that drill will cost you about $4,000. And don’t forget the cost to replace the radiator you had to pop a hole in.

RAY: So as you suggested, this is a harebrained idea. You’re much better off with one of those portable “jump packs” that you can use to jump your battery. The most powerful one you can get (which is what you should look for, in terms of the amps it produces) will cost you less than $200. That’s the way to go.

•Q. My daughter has a Volvo named Smelly. It has a very distinct chemical smell that we cannot get rid of. We have had the car detailed, we’ve put an ozone machine in it for four days, we’ve left the doors open for days in the sun -- nothing puts a dent in the smell. She is 17 years old and drives to school every day, 45 minutes each way. She is in the car a lot, and I am concerned that it is unhealthy for her. Some of her friends say it smells like crayons.•

RAY: Does it smell like the Crayola 64 box with the built-in sharpener? Or more like a box of Dixon-Ticonderogas?

TOM: This one’s actually a mystery to us, as well as to many other people. There’s a minor epidemic of European car owners having flashbacks to first grade when they’re driving.

RAY: VW owners seem to complain the most about this mysterious crayon odor, but we see complaints from Volvo, Mercedes and BMW owners, too. And no one seems to know what material in the car is causing it.

TOM: If you haven’t already, you might as well ask your mechanic to take a sniff. Because if it’s not this Mysterious European Crayon Odor, it could be something common, like a small oil leak from the valve cover, or a leaking heater core, and an experienced mechanic should be able to identify it with a sniff or two.

RAY: You’ll have to find a mechanic in the “sweet spot” of his career, when he’s smelled enough leaks to know right away what it is but hasn’t smelled so many leaks that the inside of his nose is charred and useless.

TOM: Once you know what kind of a leak you’re looking for, you’re more than halfway to fixing it.

RAY: But my guess is that it’s not going to be oil or coolant (or an old magenta crayon that some kid pushed into the vents 100,000 miles ago). And your mechanic will be as stumped as everyone else is.

TOM: Speculation centers on the leather used for the seats of those cars (which does have an odd smell, although I would describe it more as “decaying carcass” than “crayon”), or the sound-insulation material that keeps engine and road noise from being overwhelming.

RAY: But it’s really speculation, as far as we can tell. So let’s ask your fellow readers for help. If anyone has had this crayon odor, and has had success in positively identifying it and getting rid of it, drop us a note and let us know. If we get anything that’s more than just speculation, we’ll pass it along.

TOM: In the meantime, if your daughter starts having visions of coloring books, have her roll down the windows.

Got a question about cars? Write to Click and Clack in care of this newspaper, or email them by visiting the Car Talk website at www.cartalk.com.