• Q. My car time-travels into the future. I have a 2004 Volvo XC70 station wagon (I know it’s dowdy, but it’s better than a minivan, right?) that for some reason does not keep proper time. I can set the clock to the correct time, and within days it will be running fast. Within two months, the clock is fast by 20 minutes. I can understand losing time because of a weak battery or something, but advancing in time? Any thoughts?

OK, let me clarify that: Any thoughts pertaining to my question? •

TOM: We actually do have a few of those.

RAY: If you’re the kind of person who is chronically late, you may have a spouse who is surreptitiously nudging your clock ahead in an attempt to get you to be on time.

TOM: Several of my ex-wives used to try that on me.

RAY: Oh, I don’t think they wanted you to be on time. They were just trying to make the day of the divorce settlement come sooner!

TOM: Most likely, the clock itself is faulty. And, unfortunately, the clock in this car is part of the instrument cluster.

RAY: And when you find out that in order to replace this clock, you have to replace the whole instrument cluster for $1,000, you’ll embrace the time-honored solution for malfunctioning automotive clocks.

TOM: You’ll go to the hardware store, and for four bucks, you’ll buy yourself one of those stick-on digital clocks. You’ll peel off the backing and slap it right onto the instrument panel, over where your current clock sits.

RAY: Now, it’s possible that your entire instrument cluster is beginning to fail. If something crucial in the cluster stops functioning -- like the speedometer -- you may be forced to replace the whole thing at that point.

TOM: Or, if you’re lucky, your regular mechanic will know one of the places that fixes these panels for a few hundred bucks, and he’ll be able to send it out for you.

RAY: But I wouldn’t bother just for the clock. Even if you’re a Volvo owner and you’re used to leaving the dealership with angina after seeing the estimate, that’s a lot for a clock. Especially given the age of the car and the price of the alternative. Good luck.

• Q. I love your show. I recently got a 2001 Audi A8L that now has 130,000 miles on it. The only other owner was my dad, and he took extremely great care of the car. Recently, the check-engine light has been coming on, saying that my catalytic converter’s efficiency is too low. My mechanic tested it and said the level is just barely above what I need for the car to pass its emissions inspection. He said to wait as long as I can to replace it, but that some people choose to get rid of their cars at this point because the repair is $5,200, and the blue-book value of the car is only $6,000. So, what should I do? Keep the car and pay $5,200 to replace the converters when the time comes, or sell it now, while it is still passing its emissions tests? •

TOM: You have to relocate to somewhere with no emissions testing. Have you considered the Democratic Republic of Congo?

RAY: A lot of people don’t realize that when you buy a high-end car, it’s not only the purchase price that’s high -- the parts and service are “premium priced,” too.

TOM: But the price you got sounds a little high even for Audi. This car uses two catalytic converters. According to our sources, the converters themselves cost about $1,900 if you buy them from Audi. Then you probably should replace all four oxygen sensors, at about $200 a pop. And then add labor. Still, I don’t see how they can charge you more than about $3,500 for this job. So I think the estimate you got is high.

RAY: Not that $3,500 is cheap! But if someone offered you this car, right now, with new catalytic converters, for $3,500, you’d probably buy it, right? After all, what’s your alternative? You could sell it for $6,000 and get what? A 2004 Dodge Caravan?

TOM: Or, if the buyer finds out why your check-engine light is on, you’ll sell it for $2,500 and get a ’94 Caravan!

RAY: You also can research aftermarket converters. There are people who actually rebuild converters and ship them to you. You can find these guys online. Of course, you don’t know what kind of quality you’re getting when you go that route.

TOM: We’ve had some rebuilt converters that worked well, and others that didn’t do enough “conversion” to keep the check-engine light off (which means you can’t get an inspection sticker). So you can save some money that way, but you’re taking your chances.

RAY: Since this is still a nice car, and it’s been well cared for, and you seem to enjoy driving it, I’d say bite the bullet and replace the converters. But shop around first and see if you can get a better price.

Got a question about cars? Write to Click and Clack in care of this newspaper, or email them by visiting the Car Talk website at www.cartalk.com.