This is really baffling me, and I’ve come up with several possible explanations: (1) Remember the movie “My Cousin Vinny” when Marisa Tomei gives her courtroom explanation of Positraction? I am thinking that maybe there’s a similar system in my Saab that’s causing this phenomenon. (2) Maybe the front wheels spun unequally on ice. (3) When taking a corner to the left, maybe the left wheel spins less than the right one does. In any case, please provide an explanation for this. I know it doesn’t really matter how the hub covers are positioned, but it’s driving me nuts. — Phil
RAY: Not a lot to keep you busy in the dead of the New Hampshire winter, eh, Phil?
TOM: Explanation 3 is the correct answer. Turning left or right forces the wheels to turn at different speeds (although wheels spinning unevenly on ice could make it happen, too).
RAY: Here’s how it works. Imagine that you could park your car on a large, clean surface, like the beige wall-to-wall carpet in your living room.
TOM: And imagine you could dip each tire in ink so you can track where it goes. In fact, you might want to try this, Phil. Your wife’ll probably get a kick out of it.
RAY: If you then turn the front wheels to the left and drive the car in a circle, the right, front wheel will make the largest circle — near the outside wall, behind where your sofa used to be. That means it’s traveling farther — and faster — than any other wheel. The left, rear wheel will make the smallest circle, and travel the least distance. And the other two wheels will be somewhere in between.
TOM: This is exactly what happens every time you make a turn of any kind on the road. The wheels all travel at different speeds, and travel different distances.
RAY: And because each wheel is turning a different number of revolutions, the little Saab logos end up pointing in random directions.
TOM: It didn’t take 10 weeks for them to get out of alignment, either, Phil. If you reset them now, and then move the steering wheel at all while you’re backing out of your driveway, they’ll be out of alignment again by the time you get to the end.
RAY: Of course, if you keep driving, chances are that at some point, they’ll end up back in alignment again. Right? They have to, at some point.
TOM: Sure. So here’s your new winter project, Phil. Stop the car after every few turns, hop out and have a look at the hub covers. And write to us and let us know as soon as all the planets align again.
In extreme cold, block heaters should be used
Dear Tom and Ray:
I live in interior Alaska, and it gets cold. How cold, you ask? It’s been -40 F (that’s negative 40) for the past week or so. My husband and I go back and forth as to whether to keep the car’s block heater plugged in all the time, or whether to use a timer and run it only some of the time. I’ve heard that too much heat is bad for the oil. This morning I used the timer, and my car decided it was too cold for the transmission to engage. I was stuck. At -45 F, I don’ t have to go to work. At -40 F, I do (administrative policy). I want to use this as leverage to get my husband to let me keep my car plugged in more of the time. What do you think? — Christie
RAY: I’d use the timer, Christie — a timer that turns the block heater on around Oct. 1 and turns it off around June 30.
TOM: In fact, you may want to buy a trailer with a diesel generator bolted onto it, so you can stay plugged in while you drive around, too.
RAY: When it’s that cold out, just leave it plugged in all the time if that’s what the car needs. The only cost is electricity. You won’t do any harm to your oil.
TOM: Right. When people talk about heat being an enemy of motor oil, they’re talking about oil that’s being overworked under hard driving conditions — like driving a car at high speeds for long distances in the heat of the summer, or pulling a trailer up the Rockies.
RAY: When you subject your engine to extreme conditions like that, it can run hotter than it’s supposed to. That can shorten the life of the oil. That’s why manufacturers recommend that people who use their vehicles for such “severe duty” change the oil more frequently.
TOM: But in your block heater’s wildest dreams, it never could get the engine oil hot enough to do it any damage. Not even close. In your case, it’s just warming it up.
RAY: So for weeks like the one you just had, you can run the block heater as much as you need to. And when it gets so cold that the block heater needs its own block heater to get started, it’s time to move to San Juan, Puerto Rico, Christie.
Send your comments or questions for Tom and Ray to: Car Talk Plaza, P.O. Box 3500 Harvard Square, Cambridge, MA 02238. Listen to them Saturdays at 10 a.m. on 91.3 FM or 88.5 FM. Visit them on the Internet at www.cartalk.com.
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