PIP4499B: Start Up Lifter Tick Noise After Engine Has Been Off For 2 Hours Or More
#PIP4499B: Start Up Lifter Tick Noise After Engine Has Been Off For 2 Hours Or More - AFM Engines - keywords BQMI - (Oct 29, 2009)
Subject: Start Up Lifter Tick Noise After Engine Has Been Off for 2 Hours or More - AFM Engines
Models: 2007 Cadillac Escalade
built before April 1, 2006 with 6.2L L92 Engine
(these engines were built with AFM Hardward but the AFM system was disabled)
2009 Buick Lacrosse Super, Allure Super (Canada Only)
2007 Buick Rainier
2010 Chevrolet Camaro SS
2007-2010 Chevrolet Avalanche, Silverado, Suburban, Tahoe, Trail Blazer
2007-2009 Chevrolet Impala
2007 Chevrolet Monte Carlo
2007-2010 GMC Envoy, Sierra, Yukon
2007-2008 Pontiac Grand Prix
2008-2009 Pontiac G8
2007-2009 Saab 97x
With an AFM (Active Fuel Management) V8 Engine:
(RPOs L76, L94, L99, LC9, LFA, LH6, LMG, LS4, LY5)
This PI was superseded to remove non-AFM engines from this PI because there is no longer an updated lifter in the works for non-AFM engines. Please discard PIP4499A.
Important: This PI only applies to AFM V8 engines above. It does not apply to Non-AFM Engines. If you are dealing with a Non-AFM engine that is experiencing a similar noise, please refer to the latest version of PIP4725.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Some customers may comment on a lifter tick noise that occurs after the engine has been off for at least 2 hours and can last for several minutes. In most cases, the noise will last less than 2 seconds, which should be classified as a short duration tick noise. While in other cases, the noise may last longer than 10 seconds, which should be classified as an extended duration tick noise.
This may be the result of dirty/low engine oil. dissolved air in the oil, low internal lifter reservoir level, and/or debris in the lifters.
Recommendation/Instructions:
If the SI diagnostics do not isolate the cause of this lifter tick noise and normal oil pressure is noted during the concern, perform the following suggestions as necessary:
1. Check the oil condition and level. If it's more than 1 quart low or if poor oil quality is noted, change the oil and filter, and re-evaluate the noise. Allow at least a 2 hour soak time between start ups when re-evaluating the noise.
2. If the tick lasts long enough, perform a cylinder power balance test with the Tech 2 to cancel each fuel injector while listening to the noise. If the noise is eliminated, or greatly improved, each time a specific fuel injector is cancelled, there is most likely a concern with the related piston pin or piston to cylinder wall clearance of that cylinder. If this does not isolate a specific cylinder, continue to the rest of the steps below.
3. If an extended duration tick is experienced from more than 1 lifter, replace the oil pump and oil pump o-ring to address potential dissolved air in the oil. Generally, this will not affect oil pressure or cause obvious air bubbles in the oil that can be visually identified.
4. If an extended duration tick is experienced from a single lifter, use the information below to determine if the suspect lifter pack is equipped with Eaton lifters or Delphi lifters. Replace all of the lifters on both banks if Eaton lifters are present. Replace all of the lifters on the suspect bank if Delphi lifters are present. The new lifters from GMSPO should be Delphi lifters.
• AFM Lifters:
• 1) Eaton - 3 Slots in Tube
2) Delphi - No Slots in Tube
• Non-AFM Lifters:
• 1) Eaton - 2 Parallel Clip Wires Visible
2) Delphi - 3 Clip Wires Visible
5. If a short duration tick noise is experienced and none of the information above helps, updated AFM lifters will most likely be needed to repair the noise but they will not be available until Spring 2010 at the earliest. They were supposed to be available during the 4th quarter of 2009 but further validation work is needed. This P.I. will be updated with additional information as soon as they are available. Replacing the lifters with the ones currently in GMSPO stock may not repair a short duration tick noise.
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Originally Posted by gr8lover
