Some 1999-2004 S80 models, as well as 2001-04 V70, V70XC, XC70 and S60 vehicles, may produce a humming or resonance-type sound from the front suspension while being driven at road speed. One likely cause of the noise, says Volvo, is the front strut spring vibrating against the spring seat. Installing new rubber insulators on the upper and lower spring seats (part No. 30666314, upper; part No. 30748995, lower) should eliminate the noise immediately. Volvo recommends installing the insulators on both struts, even if only one is making the noise.
The driver of a 2004-05 Jetta or 2004-06 New Beetle may come into your store with a complaint that his fuel gauge never reaches the Full mark, even after topping up the tank with fuel. While a bad fuel sending unit might be the cause, a more likely scenario is that the instrument cluster software isn't capable of recognizing changes in the signal from the sending unit. Reprogramming the cluster with new software is the only surefire fix. Check with a dealer for the specifics of the reprogramming job.
The owner of a 2006-08 Buick Lucerne or Cadillac DTS may come up to your write-up desk with a complaint of front brake noise and/or a pulsation from the pedal while braking down steep hills.
According to GM, the problems affect vehicles that are driven primarily in mountainous terrain and are caused by the front brake pads running too hot and causing heat damage to the rotors. Replacing the rotors and installing a set of new-design brake pads that can withstand the rigors of extreme braking, part No. 25837407, should help eliminate further trouble.
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected]