Front End Rattle Sound at Highway Speeds

A whine, rattle or flutter sound may be heard coming from the front end of some 2020 Blazer models when driving at highway speeds. The sound is dependent on wind direction, so it may only occur while driving in certain directions.

Check the front upper aero shutter lower air guide seal. The seal may not be properly nested between the front impact beam and the front fascia grille blocker/EA foam.

The lower air guide seal may not have the proper preform, which allows it to lay on top of the front fascia grille blocker/EA foam. (Fig. 8, A) If the rubber seal is not tucked between the grille blocker and front impact beam, it may produce the rattle or whine sound when exposed to highway speed winds.

To correct the condition, remove the front fascia assembly and manually roll the lower air guide seal over and down the top of the impact beam. (Fig. 8, B)

Fig. 8

When reinstalling the front fascia assembly, ensure that the lower air guide seal is positioned between the front impact beam and the fascia assembly. It may help to apply adhesive tape to the forward edge of the seal to hold it in proper position before installing the front fascia assembly.

Refer to Bulletin #20-NA-146 for additional information.

– Thanks to Pamela Francisco

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