Lash Adjuster Tick Noise on 1.6L Engine - Bleed Air or Inspect Adjusters - keywords cold lifter low mileage rattle tappet valve

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

On rare occasions, a valvetrain tick noise may be experienced. If this noise occurs after being parked with the engine off for an extended period of time, this noise may be the result of air that is trapped in the valve lash adjusters. This may also be the result of a collapsed valve lash adjuster plunger.

If a valvetrain noise is encountered as described above and the SI diagnostics do not isolate a concern, the following information may be helpful:

1. Increase the engine RPM to 2,000 - 3,000 RPM and hold it there for 3 - 5 minutes to purge any trapped air out of the valve lash adjusters. It may be necessary to repeat this procedure up to 5 times to eliminate the noise.
2. If the noise is still present, inspect for valve lash by using a standard feeler gauge to measure between the valve lash adjusters and the base of the each cam lobe while the related piston is at top dead center. There should not be any valve lash present since these are hydraulic valve lash adjusters. If any valve lash is present, replace each valve lash adjuster that is collapsed with the existing part numbers that are listed in the GMSPO catalog.

Notice: Due to different part suppliers, there are 2 different valve lash adjuster styles available for this engine, which are interchangeable with each other.

Important: This procedure should not be performed for lower end engine knock noises.

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.