Buzz or Rattle Noise While Driving Under Load from the Exhaust - keywords 3.5L hear L52 nut RPM shield
| Subject: | Buzz or Rattle Noise While Driving Under Load from the Exhaust |
| Models: | 2004-2005 Chevrolet Colorado |
| 2004-2005 GMC Canyon |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Buzz noise from the engine compartment or exhaust area. This may occur while the engine is under load or driving with the RPMs between 2200 and 2800 under load. The noise may also sound like it is coming from the air cleaner area. This concern only applies to the L52 3.5L engine.
Recommendation/Instructions:
Inspect the exhaust manifold for a loose exhaust heat shield. The suspected fastener positions are noted below, however all fastener positions need to be inspected. Make sure that the shield itself is not in direct contact with the manifold other than at the fastener positions. Reposition the shield if necessary to avoid the contact. It will be necessary to maintain a 10mm gap between the exhaust manifold and heat shield.
- Secure the nut above the O2 sensor.
- Secure the nut on the #1 exhaust tube.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
