Rattle or Knocking Noise from Audi Camshaft Adjuster at Cold Start - Engine Builder Magazine
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Rattle or Knocking Noise from Audi Camshaft Adjuster at Cold Start


The following chart lists the production models and engines affected by this conditon.

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The camshaft adjustment is hydraulically actuated and controlled by the engine oil pressure. If the engine has been turned off for a longer time, the oil pressure drops down and the oil partially flows back into the oil sump.

To ensure an efficient camshaft adjustment right after an engine cold start, the oil pressure inside the camshaft adjusters must be built as fast as possible. During this time a rattle or knocking noise may be noticeable.


This noise is normal at an engine cold start and will last until the oil pressure is fully built up which takes about 1-2 seconds.

Do not replace the camshaft adjuster unit(s) for a noise concern as described above. Replacing the camshaft adjuster unit(s) will not eliminate this noise.

Some or all of this information was provided by the Automotive
Parts Remanufacturers Association (APRA). For more information on
technical bulletins available through APRA call 703-968-2772 or visit www.AutoBulletins.com.


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