Owners of 1996-2003 General Motors vehicles equipped with 3.1- and 3.4-liter engines (VINs E and J) may complain of oil and/or coolant leakage from the top portion of the engine.
Both leaks are most likely emanating from the lower intake manifold gasket, according to GM. A new-design intake gasket with better sealing qualities, part # 89017279, is now available to address the leakage issues.
When reinstalling the manifold, clean up all the bolts with a wire wheel and apply threadlocker sealant to the bottom four threads. To prevent leakage, GM recommends tightening the vertical manifold bolts before the diagonal bolts. Follow the torque specs from a manual.
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GM reports that some 2001-2003 Chevy Ventures, Oldsmobile Silhouettes and Pontiac Azteks and Montanas, as well as 2002-2003 Buick Rendezvous, are prone to producing a buzzing or rattling sound from underneath the vehicle.
One likely cause of the noise, according to the car maker, is contact between the inside and outside pipes of the dual-wall exhaust system. Installing an exhaust clamp to pinch the two pipes together is the recommended fix.
To zero in on the diagnosis, start the engine and let it reach operating temperature. Now shift into reverse, hold the brake pedal down and vary the engine speed between idle and 2000 rpm. If you don't hear the noise, look elsewhere for the problem.
If the buzzing or rattling sound does becomes obvious, order a heavy-duty 2½-inch exhaust clamp, part # 15712422 or equivalent. Now ask one of your fellow techs to get in the vehicle, then raise it up on a lift. Next, locate the front weld of the catalytic converter, then measure 3 inches inward toward the front pipe. This is where you'll want to position the exhaust clamp.
Install the clamp, then tighten its retaining nuts to an initial torque of 30 foot-pounds. Now have your mate put the gearshift lever in reverse while varying the throttle between idle and 2000 rpm. If the noise is gone the fix is complete. If it's still there, continue tightening the clamp nuts a little at a time until you've got sufficient pipe crush to eliminate the noise.
Some 2000 Camry models can produce a rattle-type sound when moving above 50 mph.
The most likely source of the noise, Toyota said, is the catalytic converter heat shield being forced against the body due to the air rushing in from underneath the vehicle at highway speeds.
A new stiffer heat shield is now available to address the irritation. The part number for the revised shield is the same as the old one.
“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]