Dear Car Talk:
We have a 2017 Ford F-150. It has a gas-saving feature that turns the engine off when we stop at a traffic light for more than a couple seconds.
My husband turns the switch for this feature to “off” every time he starts the truck. He thinks it’s hard on the engine to stop and start over and over.
If that’s true, why is it offered as a feature? I agree that what he thinks makes sense, but I’m confused as to why it came with the truck then (I always leave the feature on, mostly because I forget about it until I stop).
What is the answer? I enjoy your column very much.
Thank you.
— Cathy
The reason almost all new cars come with automatic stop-start systems is because they save fuel and cut down on pollution.
They’re especially useful in cities, where cars spend an inordinate amount of time sitting still, like 4,000-pound mobile air conditioners. But even in suburban and rural areas, there’s no good reason to waste fuel and pollute the air while you sit, doing nothing, for 60 or 90 seconds at a traffic light.
The reason they offer an “off” switch for this feature is because, depending on how well it’s executed, the stopping and starting of the car can be annoying to the driver. We drove a Chevy Traverse where the stop-start system was practically undetectable. The next week, we drove a Subaru Forrester in which it drove us bonkers and made the whole car shudder every time it restarted.
To answer your husbands concern, the engine really couldn’t care less how many times you start and stop it. In fact, the less it runs, the longer it lasts. So arguably, you’re prolonging the life of the engine by allowing it to shut off regularly.
There was some concern that these systems might lead to early failure of starter motors. In reality, we just haven’t seen those problems yet. It’s possible they’ll develop in the coming years. And, in fact, if your husband is really convinced they will, he might want to put your IRA in starter-motor futures. But, given the big picture, and the positive effect these things have on the air we breathe, my advice to your husband would be to use the system, unless it drives him crazy.
Of course, he won’t take my advice, so that’ll be my advice to you, Cathy. We’ll make you a bumper sticker. “Save the planet: Don’t turn off the stop-start feature.”
Dear Car Talk:
I have a 2004 Subaru Outback, 6-cylinder. It makes a high-pitched humming noise, like millions of crickets, after I drive at freeway speed, but only after about 10 minutes on the road.
It stops when I brake, then resumes. Oh, the Outback does have 272,000 miles on it.
— Joy
Congratulations, Joy. It’s nice to see you marking the 50th anniversary of the moon landing by driving this car the equivalent of to the moon and part way back. Unfortunately, all you’ve got to show for it is a brake pad noise.
It sounds like you have a brake pad that’s sticking, causing it to rub against the disc rotor. Normally, the brake pads sit right against the disc rotors, and even touch a little bit, but not enough to slow down the car, or make any noise. Then, when you press the brake pedal, the brake caliper causes the pads to squeeze the spinning disc rotor, which is what stops the car.
Based on your description, it sounds like one of your calipers is sticky. So when you first start driving the car, everything is OK. But after about 10 minutes (and, more importantly, several applications of the brakes), the caliper fails to retract all the way, and leaves a pad pushed up against the rotor.
That’s what’s making the sound of a million crickets — the pad continually rubbing against the disc rotor as the wheel turns. When you actually use the brakes, and the pads are pushed tightly against the rotors, the noise temporarily goes away.
You should get this fixed, Joy. It’ll eventually get worse. The danger is that if your brakes are always lightly applied, you can overheat the brake fluid. And if your brake fluid overheats and boils, it can’t transmit hydraulic pressure, and your brakes won’t work.
Ask your mechanic to check your brakes. In particular, ask them to check for a sticky caliper. But when you go, bring some smelling salts with you. On a car this age, especially if the brakes have been neglected for a long time, you could easily end up needing $1,000 worth of brake work. You could need pads, rotors and a caliper rebuild.
But if that’s what it takes to make the car safe, do it, Joy.
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. Send comments to editorial@therepublic.com.
