Owners of 2003-05 Jeep Cherokee and Liberty models, as well as 2003-06 Wranglers (all with 2.4-liter engines), may complain of an annoying chirping sound at idle. Chrysler says the noise occurs most frequently in higher ambient temperatures, and is most likely due to the accessory drive belt slipping on one or more pulleys. Changing the belt routing and/or replacing the belt with an improved design (Part No. 04892519AB, without a/c; Part No. 04892520AB, with a/c) should eliminate the noise condition.
To figure out what approach to take, just look up the year of the vehicle. For 2003-05 models, you'll have to alter the belt routing by removing the No. 2 idler pulley, as shown in the illustration above. The pulley is no longer necessary. Then just install the updated belt and remove the underhood belt routing label.
The No. 2 idler pulley should already be removed on most 2006 vehicles. Take a look to be sure. If the pulley is still there, remove it. If it's gone, just install the improved belt and remove the routing label.
Some 2007-08 Ford Fusion, Mercury Milan and Lincoln MKZ models with AWD systems may produce a vibration in the drivetrain while being driven at highway speeds. Ford says that the vibration is often accompanied by a howling noise, and that both problems are due to either an improperly indexed or out-of-balance rear driveshaft.
Start the repair off by disconnecting the rear driveshaft and reindexing it to the rear diff flange as outlined in a repair manual. Now go on a road test to see if the vibration and noise are gone. If they are, you're done with the fix. If the symptoms remain, replace the rear prop shaft with an upgraded unit, Part No. 8E5Z-4R602-A.
Owners of 2006-08 RX400h, 2007-08 ES350 and 2007-09 RX350 models may complain that dust or a powdery-type residue is coming out of the air conditioning vents when the blower motor is on. Lexus attributes the condition to the special coating applied to the evaporator at assembly working loose as a result of moisture in the HVAC case. New-design evaporators with an improved coating material are now available to address the problem. Order Part No. 88501-28400 for ES350 models, Part No. 88501-48251 for RX350 models and Part No. 88501-48171 for RX400h models.
"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].