The News on Noise [Vibration and Harshness].
Noise, vibration and harshness (NVH) are the three words used to categorize the rattles, squeals, shakes, bumps and whistling sounds that disrupt the ride. So, how can you help customers stop the noise? This primer on NVH looks at some real-world problems that can be fixed quickly with the help of a Technical Service Bulletin (TSB).
Many BSR complaints (such as loose trim) can be serviced using various tapes and lubricants. Tapes, including foam, flock and anti-squeak, can be used to eliminate noises caused by metal, plastic and vinyl components. Long-life lubricants and greases can also be used on a variety of components to keep NVH at bay. Here are some that help.
Itch and squeak tape is an abrasion-resistant material that conforms to many irregular surfaces. It can be applied between metal and metal, metal and plastic, and vinyl and plastic. Common applications are trim panels and bezels. The temperature range for its use is -40º to 225ºF. Open cell foam tape also conforms to irregular surfaces. It is used as a wire harness and connector wrap.
Black nylon flock is an aggressive acrylic adhesive that provides cushioning. It is also used to isolate components and it’s water resistant. It can be applied between metal and metal, metal and plastic, and vinyl and plastic. Applications include bezels, ducts and cowl panels. The operating temperature range is -40º to 180ºF.
For noise issues on the chassis, NYE® Grease 880 is excellent for reducing noise on strut bushings and sway bars. Lubricants that do not harm plastic or rubber include Krytox® oil and grease. The oil product is great for hard-to-reach places as it migrates to the source of the noise condition. Both have a wide operating temperature range of -30º to 400ºF.
Not Good Vibrations
Vibrations that can be felt in the steering wheel, or in the driver/passenger seats, are not uncommon. These conditions can result from tire/wheel imbalance, excessive wheel runout and variations in tire road forces. In most cases, these vibrations are most notable at highway speeds of 60 mph or more.
Visual inspection is the first step in diagnosing these problems. Verify the correct wheel and tire combination is being used. Also, look for the presence of wheel weights. Next, inspect the tires and wheels for damage, ice/mud packing and unusual wear.
Shakes, Rattles and Rolls
From time to time, a very specific problem arises on a certain model(s) built during a stated time period. When such problems do occur, a Technical Service Bulletin will be issued. This bulletin will address the symptom, the cause and the right correction to take care of the problem. Let’s take a look at a few.
Bulletin 21-010-13, dated October 23, 2013, deals with a rattle noise in the shift lever boot in the 2012-2013 Dodge Dart. This applies only to vehicles built between April 25, 2013, and July 5, 2013, equipped with an automatic transmission.
For this noise, the fix is simple. It involves adding two-sided tape to the shift level bezel. That’s it. That solves the problem.
Another rattle issue is addressed in Bulletin 23-005-14. The applicable vehicles are the 2012-2013 Dodge Caravan, Grand Voyager and the Chrysler Town and Country. It applies to vehicles built between September 9, 2011, and March 6, 2013. A rattle, tick or squeak can be heard from the instrument panel area.
The cause of the noise is touch condition (metal-to-metal contact) under the cowl panel cover in either the right or left corner of the plenum below the hood hinge. So, the noise doesn’t originate in the instrument panel, but it sounds as if it does. To verify the condition, drive the minivan over a variety of road surfaces. When the noise occurs, touch a number of surfaces inside the vehicle, including the instrument panel and dashboard. If the noise does not stop, continue with the repair procedure outlined in the bulletin.
Look for metal-to-metal contact of a sheet metal tab contacting the body inner panel and the outboard end (rear corner) of the plenum. This area is under the hood hinge on the side where the noise was most noticeable. Using a pry bar, move the plenum sheet metal tab away from the body inner panel. Another simple fix to eliminate the noise.
Bulletin 23-022-12 REV A deals with a knocking sound from the instrument panel near the A-pillar. The target vehicles are the 2011-2012 Dodge Durango and Jeep® Grand Cherokee built prior to July 2, 2012.
An audible BSR, or knocking sound, appears to be coming from the instrument panel area, at or near the leading edge of the A-pillar. The noise might actually be caused by an improperly adjusted front hood hinge. The hood hinge can be checked in the closed position. Grasp the hood near the rear corners at the hinge and lift up and down. If there is excessive movement and/or a knocking sound is produced, there’s the problem. Perform the repair procedure as outlined in the bulletin.