Owners of 2005-06 Matrix or Corolla models with 1ZZ-FE engines may complain of a drone-type noise or vibration when accelerating the vehicle up to 30 mph from a stop. One probable cause for the trouble, says Toyota, is a damaged right-side engine mount. Installing an improved, new-design mount, part No. 12305-0D120, should eliminate either condition.
Chrysler reports that some 2004-06 Pacifica models may be difficult to start or may not start at all when the outside temperature is below freezing. According to the carmaker, the problem afflicts 2004 3.5-liter vehicles built after July 12, 2003, all 2005 vehicles with both 3.5-liter and 3.8-liter engines and 2006 3.5-liter vehicles built before Feb. 28, 2006. A defective idle air control (IAC) motor is the likely culprit.
Installing a new-design IAC motor and reprogramming the PCM with updated software should eliminate the starting troubles. For the IAC motor, order part # 04861325AD for 2004 3.5-liter and 2005 3.8-liter engines; or part No. 04861625AB for 2005-06 3.5-liter engines. As for the reprogramming job, check with a dealer for the specifics of the flash.
Some 2005-07 two-wheel-drive F-250 and F-350 Super Duty pickups built before 7/21/06 may produce a humming or grinding sound from the front axles while on the open road.
According to Ford, one probable source of the noise is a worn front wheel bearing. The bearing wears prematurely due to water, sand and other road debris getting into the roller cage via the grease seal. The problem can occur at one or both sides of the truck. Replacing the bad bearing and installing an updated disc brake shield which incorporates a protective foam seal to keep out the elements should prevent further noise issues. Order part No. 7C3Z-2B159-B for the right-side disc shield; part No. 7C3Z-2B159-A for the left-side shield.
"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]