Dear Car Talk:

I have a 2017 Jeep Cherokee V-6 with the automatic stop-start feature. Which is best in the long run: Disable the feature so that the engine continues to run at stoplights, just like all the previous cars I've had, or let it shut itself down and then restart when I take my foot off the brake? Is the amount of gas saved at a two- or, very occasionally, three-minute stoplight better than the added use of the starter? Does this cause enough added wear and tear on the engine to be concerned about? -- Joseph



These stop-start systems are just a few years old now, so I'll reserve the right to change my mind if evidence to the contrary piles up. But from what I've seen so far, the starting systems have been beefed up enough to handle the extra starts without any sort of long-term issues.

So if there's really no penalty for stopping and restarting the car when you're not moving, then why not save the extra fuel -- as well as the wear and tear on the engine?

More importantly, when the engine is off, you're not creating any pollution. And in cities, if we collectively reduce car-generated air pollution by 3 to 5 percent, that'd be great.

The only reason we've had to turn off stop-start systems in cars we test-drive is that they can be annoying. Some are better than others. Many are subtle enough that you very quickly get used to it; others start with a 1.1-Richter shudder that makes you want to run under a doorway to protect yourself. I imagine that all of these systems will continue to improve over time to where they're not only tolerable, but we basically forget all about them.

So unless the restart is so extreme that it's causing you neck pain, Joseph, use it, save the fuel and cut the pollution.