M62 V8 Timing chains

[peaktorque]

How long do they last? My 140,000 mile 535i sounds a bit 'timing chainy' on idle. Tensioners?

Thanks

[paoloh]

I always thought 140 to 160 was a chains life

[peaktorque]

It is a duplex chain set-up so I would have thought it should last at least 200,00? Or could it be vanos related?, as it does seem concentrated at the top of the engine.