Exhaust Rattle, Buzz, Pop or Whistle – 2014 Chevrolet Silverado & GMC Sierra 1500

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Bulletin No.: PI1201A
Date: April, 2014

Subject:	Exhaust Rattle, Buzz, Pop or Whistle
Models:	2014 Chevrolet Silverado 1500
	2014 GMC Sierra 1500
	Equipped with 4.3L, 5.3L or 6.2L Engine (RPOs LV3, L83, L86)
	Built Prior to December 8, 2013 or Muffler Julian Date of 352 2 (See Below)

 

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This PI has been revised to add the 6.2L Engine. Please discard PI1201.

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Condition/Concern #1

Some customers may comment on a rattle, buzz and/or pop (oil canning) noise heard coming from the exhaust system under different conditions.

 

Recommendation/Instructions #1

The correction of the muffler pop or oil canning noise will require the replacement of the cold end or back half of the exhaust system.

Note: The exhaust system rattle can also be diagnosed by tapping on the bottom of the muffler.

 

Condition/Concern #2

Some customers may comment on a whistle type noise that can be heard coming from the muffler area.

 

Recommendation/Instructions #2

1. Temporarily lock the Passive Exhaust Valve (PEV) in the open position, located behind the muffler, as shown in the illustration above.

2. Rotate the Passive Exhaust Valve (PEV) counterclockwise as shown in the illustration above.

 

3. For testing purposes only, obtain a 1/4″ x 20 x 2” steel bolt, nut, lock washer and two large standard 1/4″ x 1” outside diameter washers (body washer), and install the bolt as shown in the illustration above.
4. If the condition is reduced or changes greatly in severity, replace the exhaust system.

 

Condition/Concern #3

Some customers may comment on a vibration in the seat or steering wheel felt when the truck engages V4 mode (Active Fuel Management).

 

Recommendation/Instructions #3

1. Verify the condition.
2. Review exhaust system for Ground Outs at the mounts and repair as necessary.

3. For testing purposes only, obtain a 1/4″ x 20 x 2” steel bolt, nut, lock washer, and two large standard 1/4″ x 1” outside diameter washers (body washer), and install the bolt as shown in the illustration above.
4. If the condition is reduced or changes greatly in severity, replace the exhaust system.

 

Parts Information

Description	Usage	Part Number
MUFFLER, EXH (W/EXH PIPE)	CK155 (43) 4.3 (LV3), 5.3-C (L83), CK157 (53) 4.3 (LV3) , 5.3-C (L83)	20757703
MUFFLER, EXH (W/EXH PIPE)	CK157 (03) 4.3 (LV3), 5.3-C (L83), 6–SPD AUTO TRANS (MYC)	20757704
MUFFLER, EXH (W/EXH PIPE)	CK157 (43) 4.3 (LV3), 5.3-C (L83)	20757702
MUFFLER, EXH (W/EXH PIPE)	CK159 (03) 4.3 (LV3), 5.3-C (L83)	20757701
MUFFLER, EXH (W/EXH PIPE)	CK157 (43) 6.2 (L86)	23199937
MUFFLER, EXH (W/EXH PIPE)	CK155 (43) 6.2 (L86), CK157 (53) 6.2 (L86)	23440153

 

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation	Description	Labor Time
4051980	Exhaust Muffler Replacement	Use Published Labor Operation Time

 

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