2016 GMC Truck Acadia AWD V6-3.6L Technical Service Bulletin # 07-06-04-025D Date: 100107

2016 GMC Truck Acadia AWD V6-3.6L Technical Service Bulletin # 07-06-04-025D Date: 100107

Fuel System - Clicking/Ticking Noises On Cold Start Up

INFORMATION

Bulletin No.: 07-06-04-025D

Date: January 07, 2010

Subject: Information on Clicking/Ticking Sound/Noise Heard During Cold Start, Sound/Noise Decreases But Continues as Engine Warms - Normal

Operation of High Pressure Fuel Pump and Injectors

Models:

2009-2010 Buick Enclave

2010 Buick LaCrosse

2008-2010 Cadillac CTS, STS

2010 Cadillac SRX

2009-2010 Chevrolet Traverse

2010 Chevrolet Camaro, Equinox

2009-2010 GMC Acadia

2010 GMC Terrain

2010 Saturn OUTLOOK

Equipped with 2.8L, 3.0L or 3.6L VVT Direct Injection V6 Engine (VINs 4, G, D, V - RPOs LAU, LF1, LLT)

Supercede:

This bulletin is being revised to include additional models and engine RPOs. Please discard Corporate Bulletin Number 07-06-04-025C (Section 06

- Engine/Propulsion System).

The 2.8L, 3.0L and 3.6L SIDI engines (RPOs LAU, LF1 and LLT) use a direct injection fuel system that operates at very high fuel pressures. A

direct injection fuel system produces a rapid clicking and ticking sound that can be heard from the engine compartment. The sound is more evident

when outside around the vehicle or when the hood is open. The sound is more noticeable during idle and is more frequent during a cold start, but

lessens once the engine is warm. The rapid ticking noise on cold start up is the fuel pump (located on the rear of the left cylinder head) building up

high fuel pressure. When the engine warm-up is completed, the high pressure fuel pump will continue to tick at a lower rate of approximately one

tick per second during idle. The clicking sound is the fuel injectors pulsing on and off under higher fuel pressures. These sounds are the results of a

normal direct injection fuel system operating properly.

DO NOT attempt to repair or replace any parts for this kind of clicking or ticking concern. The clicking or ticking sound is not indicative of any

concerns with the engine or the vehicle. You may wish to give the customer a copy of this bulletin.