Q: I am banking on you solving this problem. We purchased our 2010 Ford Escape XLT/AWD 4-cylinder new in March 2010. Four months later, a rattle developed when traveling at 1,500 rpm. The rattle is heard underneath the vehicle but doesn't occur all the time. The rattle can be heard over the radio and lasts 10 to 20 seconds and then it stops. The dealership finally replaced the serpentine belt tensioner and the rattle ceased for several months. Today, the third tensioner replacement was put on our vehicle. The mechanics seem to be at a loss as to what is causing this to continue to occur.

A: Ask the dealer to check Ford service bulletin 11-10-26, dated October 2011. According to my Alldata database, this bulletin covers a rattle or drone between 1,300 and 1,400 rpm generated by a resonance in the serpentine accessory drive belt. Ford has issued a new alternator/generator pulley kit to address this issue.

Q: Several months ago, the right low beam on my son's 2009 Chevy Malibu went out. He had the bulb replaced, but a month later the bulb went out again. Another month later, the bulb went out again. Are there any recalls on this problem? If not, what else can we do?

A: Carefully inspect the socket and connector for this bulb. If there are signs of electrical arcing, corrosion or discoloration, replace the connector. GM issued a service kit for this connector, and if the vehicle is still under warranty, the replacement would be covered.

Paul Brand, author of "How to Repair Your Car," is an automotive troubleshooter and former race-car driver. Email questions to paulbrand@startribune.com . Explain the problem in detail and include a daytime phone number. Personal replies aren't possible.