What's the longest you've gone on a timing belt?

John Paul Special to The Journal

Q: I have a 2008 Hyundai Sonata which is equipped with a timing chain. The vehicle is approaching 100,000 miles. I was wondering, since it is a timing chain instead of a rubber timing belt, does it need to be replaced or should I wait? I get mixed answers from people whom I've asked. Some tell me stories of the timing chains breaking and the expensive repairs thereafter, and others tell me that the chain should run the life of the engine. Can you provide some guidance?

A: As a general rule, if an engine has a timing chain and the oil was changed on a regular basis, the timing chain should last the lifetime of the engine. Timing chains can fail prematurely if the tensioners that hold and guide the chain fail, although usually there will be some engine noise or poor performance prior to the chain failing.

'160 mph' is marketing 

Q: The speedometer in my Toyota goes from 1 to 140 mph. Can my 2010 Toyota Matrix even come close to going 140 mph? In addition, it would help to have more space between 30 and 60 miles per hour when I'm trying to stay close to the speed limit. My real question is, why do car makers do this?

A: Back in 1979, there was a law that mandated that speedometers only read up to 85 miles per hour to, in theory, lessen the number of people who speed. The law was repealed a few years later. My opinion is that speedometers read the way they do for nothing more than marketing. The reality is that most cars have speed limiters, due partially to the fact that most sedans and minivans have tires that are not rated for speeds above 118 miles per hour — even though their speedometers read to 160 miles per hour.

Time for a new vehicle?

Q: The check engine light came on in my 2010 Honda Odyssey. Our mechanic quoted a  corrosion problem with the fuel tank. The repair estimate was anywhere from $800 to $1,200. The vehicle generally runs well, has 160,000 miles, and gets about 20 mpg mixed. It needed work within the past year — a timing belt and air conditioner repair. At what point does it make sense to just buy new? At what point does trade-in value reduce to "not much"? I'm just trying to find the most sensible answer.

A: According to www.nadaguides.com, your minivan has a trade-in value of $4,000 to $6,000. As a general rule, my advice has been that when a single repair exceeds half the value of the vehicle, you need to think a bit before having the repairs performed. If your minivan still performs well, is structurally sound and fits your needs, spending $1,200 on a very functional vehicle makes sense to me. A new Honda minivan can range from $30,000 to $50,000, so spending up to $2,000 per year to keep a specialty vehicle like your minivan roadworthy can be money well spent.

Road trip prep

Q: I have a 2007 Buick Lucerne, bought new, with regular service at the dealers every three to four months. It has — at present — 48,000 miles on it and seems to run great. Is it OK to drive a 10-year-old car from Boston to Chicago and return without worrying?

A: The trip is about 2,000 miles and I'm sure you have driven 2,000 miles without any incidents. My suggestion would be that before the trip, have the belts and hoses inspected; the fluids checked and topped off, if necessary; the tires properly inflated and inspected for wear and damage; and the battery condition tested. At the same time, a good technician will note any other potential problems. This should minimize any chances of problems on the road.

— John Paul is the AAA Northeast Car Doctor. He has over 30 years of experience in the automobile industry and is an ASE-Certified Master Technician. Write to John Paul The Car Doctor at 110 Royal Little Drive, Providence, RI 02904. Or email jpaul@aaanortheast.com and put "Car Doctor" in the subject field. Saturday mornings at 8:30, tune into John Paul The Car Doctor at wrolradio.com. Follow him on Twitter @johnfpaul or on Facebook.

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