20
Chain drive
The timing gear of the five-cylinder TFSI engine is located on the
power output side. It is of two-stage construction and is driven by
two different chain types.
In the first stage of the chain drive, the oil pump and an idler gear
are driven by the crankshaft. The oil pump has a low ratio. The
crankshaft also drives an idler gear, which has two tasks. Firstly, it
drives both camshafts, and, secondly, it drives the vacuum pump.
Both drives have hydraulically damped chain tensioners.
A 3/8" gear chain is used in the primary drive train (for driving the
oil pump and the idler gear). It is similar in design to the chains in
the 1.8l R4 TFSI engine and offers acoustic advantages over a
roller chain. A 3/8" roller chain is used in the secondary drive.
The entire chain drive is lubricated by the oil returning from both
camshaft phasers and by a bore in the high-pressure chamber of
the "soft" chain tensioner in the secondary drive. There is no
replacement interval for the chain drive.
451_030
Note
After assembly work on the chain drive, all seals must be replaced on each of the timing case covers. Refer to the Workshop
Manual for specifications.
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