With the 2008 EA888 VW switched from a belt to a chain, and the tensioner of the first two generations turned out weak: as the ratchet mechanism ages it does not hold its position when the engine stops and the oil pressure disappears. The oil drains overnight and the chain goes slack. The symptom looks harmless for a long time (a short, few second rattle on a cold start as the chain slaps the guide rail), and then one day it jumps, and the engine is badly damaged inside. From then on the repair is a cylinder head or an engine rebuild. Around 2012 the maker was already fitting an improved tensioner; on the old one only replacement helps, not monitoring the noise.
What to check
- Start it cold. That is the only moment it is audible: a 1 to 3 second metallic rattle
- Ask whether the chain tensioner was replaced, and ask for the invoice (the part number is the point)
- If the seller says it only rattles a little when cold, that is not reassuring but the fault itself