Some 2007 3.7-liter Dodge Ram Trucks, Durangos, Nitros and Dakotas, as well as Jeep Libertys, Grand Cherokees and Commanders (all built on or prior to 3/12/07) may produce a high-pitched, whistle-type sound while being driven.
Chrysler says the noise is particularly obvious under light acceleration in the 1,200 to 2,000 rpm range and is most likely the result of a vacuum leak at the throttle body-to-intake manifold joint. Sealing the joint with RTV sealant, part #04883971, should eliminate the condition.
Start the fix by removing the air intake tube. Next, remove the throttle body retaining bolts and position the throttle body aside.
Using the illustration above as a reference, apply a 1mm bead of the sealant to the intake manifold flange, between the two lower throttle body bolt holes, as shown.
Ensure that the sealant is inboard of the throttle body gasket. Allow the RTV sealant to skin over, then reinstall the throttle body and retaining bolts.
To complete the fix, remove any excess sealant that seeps from the joint and reinstall the air intake tube.
Owners of 1995-98 2.5TL and 1996-98 3.2TL models may complain of a growling or whining sound from one or both rear wheels.
One likely cause for the noise, Acura reports, is a water-damaged rear hub bearing. The water finds its way into the bearing by traveling from the wheel to the brake caliper, where it then enters the bearing via a deformed grease seal.
Installing parts from a new wheel bearing kit should eliminate the noise and prevent further trouble. Order part #06427-SW5-305 for 2.5TLs; or part #06427-SZ5-305 for 3.2TL models. Included in the kits are two rear bearing assemblies, two splash guards to divert the water, two spindle nuts and two grease caps.
Volvo reports that the climate control panel on some 2001 S40 and V40 models may intermittently stop functioning.
The Swedish car maker attributes the problem to voltage spikes being introduced into the panel via the blower motor. Installing a newly designed harness with a built-in suppression diode between the blower motor and its connector should keep the voltage spikes in check. The harness goes by part #30858845.
Drivers of 2005-07 Relay minivans may come into your store with a complaint that the headlights and/or interior lights flicker from time to time.
Saturn reports that the problem usually occurs at idle with one or more accessories on and attributes it to fluctuations in alternator output.
A defective voltage regulator is the probable culprit. Installing an upgraded regulator from a special kit, part #25854910, should help eliminate the annoyance.
Drivers of 2002-03 2.5-liter Altima models with automatic transmissions may complain of a buzzing sound at 2500 to 2700 rpm under moderate acceleration.
The most likely cause of the noise, Nissan reports, is the automatic transmission breather tank retaining bracket contacting the left/front subframe rail.
Begin the fix by removing the breather tank bolt. Next, order felt cloth tape, part #68370-4B000, and install it between the bracket and subframe rail.
To complete the repair, reinstall and tighten the bracket bolt, then perform a road test to verify that the buzzing noise has been eliminated.
“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]