ē Q. My boyfriend and I disagree on whether to keep the car in the garage. He thinks it cuts down on the life of the car (something about cooling the engine). I think a car lives longer if kept in a garage. I understand that a heated garage is not a good idea ó but what about just a regular attached garage? Please advise. ē

TOM: Your boyfriend is being an oil stain on the garage floor of your life. Garages are great for cars ó and for their drivers.

RAY: At the very least, a garage will protect the exterior of your car from the elements, including those acidic pigeon and pterodactyl droppings. And if it spends every night ó or half its life ó under a roof, itíll look good for about twice as long.

TOM: From what we see in real life, thatís about right. Cars we work on that are garaged look a lot better than non-garaged cars their age.

RAY: I have no idea what your boyfriend is talking about regarding engine cooling. Maybe he thinks the engine wonít cool down as fast if itís closed in a garage? Or that the heat of the engine will warm up the garage and shorten ITS life?

TOM: The length of time it takes the engine to cool down makes no difference to anything. So, as far as we know, thereís absolutely no downside to keeping your car in an unheated garage.

RAY: A heated garage is even better, even though it does create one downside for the car. If you live in the part of the country where it snows and they use salt on the roads, by storing it in a warm garage every night, you may slightly speed up the rusting process.

TOM: How? Well, letís say you drive on a cold, snowy day, and you get salty ice and slush all over the car. Then you get home at night and pull into your heated garage. What happens? The ice melts. And youíre left with salt, water and warm air ó perfect ingredients for oxidation (i.e., rust).

RAY: Whereas if you leave the car outside, and the temperature stays below freezing, oxidation is inhibited by the lower temperatures, and the rusting process slows down a tiny bit.

TOM: On the other hand, if itís snowy and icy and miserable, who cares? Thatís when you really want to have a heated garage! You want that stuff to melt off overnight so you donít have to kick it out of your wheel wells like Nanook of the North does with his dogsled.

RAY: Plus, there are some very real mechanical advantages to parking your car in a heated garage overnight. Most notably, because the oil remains warmer and less viscous, it does a much better job of lubricating your engine from the moment you start the car. You prevent a lot of long-term damage to the engine that way.

TOM: And because the coolant also is kept warmer, the heat comes faster and your butt doesnít freeze to the seats, requiring an embarrassing call to AAA and the accompanying blowtorch extraction.

RAY: Plus, you donít have to clean snow or ice off the car, so your visibility always will be excellent. And because youíre not bundled up in four hats, six hoods and 35 layers of Bronko Nagurski Long Underwear, you can actually move your neck and turn your head, which helps you be a better driver.

TOM: So, by all means, use your garage. And if youíve got a heated garage, use that, too, with the caveat that itís a good idea to get your car washed and get rid of the salt after a week in which the roads have been salted.

ē Q. I am a member of the military living in Minot, N.D. None of the mechanics in Minot, including the dealership, seem to know what is making my 2003 Toyota Tundra 4x4 truck make a loud vibrating noise. It isnít the alignment or tires, and it doesnít appear to be the bearings. The vibrations only begin around 22 mph, and then get increasingly louder/stronger up to about 45 mph, when they go away. The vibrations are there whether I am accelerating, coasting (even in neutral) or braking. To make things crazier, the vibrations go away ENTIRELY when I switch the truck into four-wheel drive. Some days (rarely) the vibrations donít show up at all. Is it harmonics, poor engineering, a problem with the differential or drive shaft? The vibrations appear to be located under the front driverís side of the car ó right underneath the driverís seat, near the wheel. Any ideas? Thanks. ē

TOM: Well, if youíre confident that the tires are well-balanced, the next thing Iíd have someone check is the drive shaft. Maybe you hit something and bent it, or maybe thereís a worn-out or seized universal joint in there. Thatís easy to check.

RAY: When they tell you the drive shaft is fine (because itís rare for a drive shaft problem to ďnot show up at allĒ some days), then youíll want to grab your wallet and hold on to it tightly and dearly.

TOM: Because then the problem is more likely in the transmission or transfer case. The fact that it goes away when you engage four-wheel drive suggests that something is worn out near the output shaft of the transmission. The dealer or perhaps a transmission specialist is the best person to investigate that.

RAY: But be aware that it may be difficult to diagnose with a high degree of certainty, and that whatever they propose to fix probably will be very expensive. So Iíd be reluctant to authorize a big repair unless you have a lot of confidence that your mechanic has absolutely identified the source of the problem.

TOM: Alternatively, you could just keep driving and wait until whatever is vibrating eventually falls off. Then you could jump out of the car, go over to the side of the road, pick it up, take a cab to the nearest parts store and say, ďGive me one of these.Ē Good luck.

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.