Owners of 2007 Dodge Ram truck, Durango, Nitro and Dakota, as well as Jeep Liberty, Grand Cherokee and Commander models (all with 3.7-liter engines) may complain of a high-pitched whistle-type noise when driving.
According to Chrysler, the condition is most obvious under light acceleration in the 1,200 to 2,000 rpm range, and likely is due to a vacuum leak at the throttle body-to-intake manifold joint. Sealing the joint with RTV sealant, part No. 04883971, should eliminate the problem.
Begin the fix by removing the air intake tube. Now remove the throttle body retaining bolts and position the throttle body aside.
Using the illustration above, apply a 1 mm bead of the sealant to the intake manifold flange, between the two lower throttle body bolt holes.
Make sure the sealant is inboard of the throttle body gasket. Allow the RTV sealant to skin over, then reinstall the throttle body, tightening the retaining bolts to 60 in-lbs. To complete the repair, remove any excess sealant that seeps from the joint and reinstall the air intake tube.
"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].