Q: I'm losing sleep over my reliable 2012 Chrysler 200 and its gas mileage. It's got more than 80,000 miles on it, and it usually gets between 20 and 23 miles per gallon on my regular drives.

I'm becoming more of an environmentalist by the day, so not getting good mileage really irks me. I'm at a place in my life where I could buy a new-to-me car, but my budget would not be high. And my Chrysler was inherited, so it's got sentimental value and no payments.

The gas mileage is the main reason to look elsewhere. Is there something I can do to improve it? Am I crazy to give up on my beloved car over guilt?

A: I can't say if you're crazy. That's something you should ask someone who knows you better. But I do think you should hang on to your Chrysler.

First of all, your mileage isn't bad. It's about what the EPA says you should expect from this car. And their estimates often run a bit high, so you're doing fine.

Second, if your primary concern is environmental, think about all of the natural resources it takes to create a new car: the metal ores, chemicals, plastics and rubber. By getting a few more years out of an existing car (unless it's a gross polluter, which yours is not), you're actually helping the environment.

Third, there's a lot you can do to be "greener" without immediately trading in your car. Have it serviced regularly to ensure that it is running well and not polluting. If there's something wrong with it — a bad sensor, stuck thermostat or sticky brake caliper, for instance — get it fixed, because things like that can lower your mileage and create more pollution. Make sure your tires are properly inflated, too, because that also affects your mileage.

And finally, you can try to drive less. Combine errands. Carpool. Walk (heaven forbid, I know). Then start saving for a serious environmental upgrade. In a few years, when the Chrysler's transmission falls out in the middle of the road, buy an electric car.

Bad timing

Q: I bought a 2009 Hyundai Accent new. Today it has 77,000 miles on it. I always kept up with my maintenance schedule, and I even had a spreadsheet with dates and mileage for maintenance. So I knew it was time to change the timing belt, but that's not cheap, so I put it off thinking I could wait.

Guess what? The motor is destroyed because the timing belt broke and ruined the head and other parts. Why would a car company make such a vital part out of rubber?

A: Manufacturers have asked themselves that question, too. And in many cases, they've switched back from rubber timing belts to metal timing chains. In fact, if you buy a new Hyundai Accent to replace the one you just lost, it'll have a metal timing chain.

The reason carmakers switched from chains to rubber belts decades ago is because when you add a chain, you have to encase it, lubricate it, add a tensioner, an idler pulley and guides. So instead of a simple rubber belt, you end up with an entire chain "system." One of the reasons that rubber belts became popular was because older chain systems broke down a lot and they were expensive to fix.

But modern chain systems are better, as is modern engine lubrication. So most manufacturers have decided that the extra complexity is worth it for the extra durability. And I'm guessing you would agree.

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