DEAR CAR TALK: I have a question that could be relevant now during the covid pandemic, while a lot of people are driving less. How long does it take for gasoline to go "bad" in a car's gas tank?
I have a Kia Optima Hybrid and a Honda Fit. In normal times, I'd fill each one up every week or two, when it got half empty, so there'd always be some fresh gas in the tank.
These days I'm only putting about 3,000 miles per year on each car. I drive each car at least once a week. If I fill up both cars, I can probably go two months (or more) before fill-ups! What's the best way to manage gasoline usage so it doesn't go bad? Thanks.
— Mark
DEAR READER: I would take a very scientific approach, and make sure you fill up each car whenever it gets close to "E." You have nothing to worry about. Most modern gasolines will easily store for a year.
You may know about the Chevy Volt, which was the first "plug-in hybrid" model on the market, debuting in late 2010. It had a battery pack, which originally gave you about 35-40 miles on a charge, and a gasoline engine, which could take you a couple of hundred miles more.
We wondered, kind of like you're wondering, what happens if I own a Volt and I drive less than 35 miles a day — as a lot of people do. In the Volt, you could easily go indefinitely on battery power alone and never activate the gasoline engine.
Well, it turns out the folks at Chevrolet thought of that, too. And they programmed the Volt's computer so that once the gasoline had been in the tank for a year, it would automatically switch the car to the gasoline engine to empty out the fuel tank and force you to refill it. And they probably erred on the side of caution. So it'd probably be fine for more than a year. Certainly, you'll be fine for two or three months, Mark.
DEAR CAR TALK: Why is it that my driver's seat belt always locks up when I pull it out, and then I have to let it go back in again and try again?
— Gregory
DEAR READER: Shy seat belt syndrome, I guess. You don't tell us what kind of car you have. Or, more importantly, what year it is. But I'm guessing you've got an older car.
Seat belts have two things to accomplish. Primarily, during a crash, they're trying to hold passengers in place and spread out the force of impact. That saves a lot of lives. Second, they're trying to be easy and comfortable to use, so that people will actually wear them and allow those lives to be saved. So seat belt manufacturers set out to engineer seat belts that would do both those things.
In the earliest days of shoulder and lap belt combinations, you may remember that the whole thing just kind of hung there, until you draped it across your body. And you had to adjust it for your size, like the seat belts we still use on airplanes. The problem was, if you wanted to lean forward to pick up the Big Mac you dropped between your knees, you had to unlatch the seat belt in order to free yourself.
So the next step was an automatic seat belt locking system that allowed people to move a bit while they were belted in. Automatic locking belts were required starting in 1996. They use one of two types of locking retractors. In each case, the seat belt is wound around a spring-loaded spool, which spins as you pull on the belt.
On your car, Gregory, that spool has a centrifugal clutch. When you pull it slowly, it unspools. But if you pull on it quickly, the centrifugal force of the spinning spool activates a pawl that locks the spool in place.
The idea is that if everything's fine, and you want to reach the radio to turn off Car Talk, as long as you do it slowly, the seat belt will unspool and let you move. But if you get in a crash, and suddenly are thrown forward very quickly, the seat belt will lock up and keep you from getting an indentation on your forehead that says "KIA." Actually, it would read "AIK."
The newer type of locking retractor uses an inertial switch, the kind your airbags use. There's a small pendulum that detects acceleration and — more importantly in this case — deceleration. On a car that uses an inertial switch, you can pull on the seat belt as hard or as fast as you want, and it'll give you slack. But if the car suddenly decelerates — like when you hit the back of a taco truck or slam on the brakes — the inertial switch locks up the retractor and protects you.
In fact, it's even more sophisticated than that on newer cars. On many cars, the inertial switch fires a pyrotechnic device that actually tightens up the seat belt and cinches you in place in preparation for impact (called a seat belt pretensioner), and then lets out some tension milliseconds later, during the crash, to keep the seat belt from breaking your collar bone or causing chest injuries (called a load limiter). We're even seeing airbags built into seat belts now to further reduce injuries.
In your case, Gregory, I'm guessing you have an older centrifugal clutch system. Those can fail as they age and lock up too easily. If you can still use the belt by pulling it out slowly, you may just want to live with it. Unless the seat belt is still under warranty (check, they are often warrantied longer than the car itself) it'll be expensive to replace.
But if it's at the point where it takes you 15 tries, and you're missing entire NFL seasons trying to get your seat belt on, then it may be time to replace the whole belt, which comes with a new retractor mechanism.
Ray Magliozzi dispenses advice about cars in Car Talk every Saturday. Email him by visiting cartalk.com