A 1999-2005 Volkswagen 1.8T, 2.8L or 4.2L model may exhibit a rattle or knocking noise from the camshaft chain tensioner(s) or camshaft adjuster(s). The camshaft adjustment is hydraulically actuated and controlled by the engine oil pressure.
If the vehicle has been sitting with the engine turned off for a period of time, the oil accumulation inside the camshaft adjusters partially bleeds off and the oil flows back into the oil sump.
To ensure an efficient camshaft adjustment after an engine cold start, the oil pressure inside the camshaft adjusters must be built up as quickly as possible. During this time, a slight rattle or knocking noise may be audible. This noise is normal at engine start and will last until the oil pressure is fully reinstated.
Do not replace the camshaft tensioner(s) or camshaft adjuster(s) for the noise concern as described above. Replacing them will not eliminate this noise.
Courtesy of ALLDATA.
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