A4 Sedan V6-2.8L (AHA) (1998)
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Timing Chain Tensioner: Technical Service Bulletins
Engine - Rattle/Knock On Cold Start-Up (Normal)
15 08 16
2010294/5
November 21, 2008. Supersedes Technical Service Bulletin Group 15 number 07-03 dated July 7, 2007 for reasons listed below.
Vehicle Information
15 Rattle/knocking noise from camshaft adjuster at engine start
Condition
Rattle or knocking noise from camshaft chain tensioner(s) or camshaft adjuster(s) for 1-2 seconds after engine start.
Technical Background
The camshaft adjustment is hydraulically actuated and controlled by the engine oil pressure. If the engine has been turned off for a long 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 up as fast as
possible. During this time, a rattle or knocking noise may be noticeable.
This noise is normal at engine start and will last until the oil pressure is fully built up, which takes about 1-2 seconds.
Production Solution
Not applicable.
Service
Do not replace the Camshaft Tensioner(s) or Camshaft Adjuster(s) for a noise concern as described above.
Replacing the Camshaft Tensioner(s) or Camshaft Adjuster(s) will not eliminate this noise.
