N57 timing chain replacement, should it be changed?

N57 timing chain replacement, should it be changed?

Author
Discussion

Mrinsignia

Original Poster:

176 posts

78 months

Sunday 16th April 2023
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I am looking to buy a BMW 640d, probably around 10 years old and with 100k on the clock. However I am a bit worried about the timing chain failing from the research I have done. Has anyone had this problem or replaced their timing chain in anticipation? Even though it is meant to be a lifelong component should it be changed?

d_a_n1979

9,683 posts

79 months

Sunday 16th April 2023
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IMO no; unless it's showing signs of needing to be changed...

This goes around a lot; if you're concerned then by all means get it changed, budget c£1500 for the job

But there are LOTS of BMWs with the N57 (and N47 etc) out there that have never had their chains replaced and they're into high miles etc

It's all about how well it's been looked after & maintained beforehand; if there are plenty of invoices/paperwork/receipts to show oil changes and their intervals then that should be spot on...

If all there is, is the service history on the iDrive and no physical paperwork to back this up; I'd walk away and keep looking, unless you want a project & can get the car at a decent price to allow for this

dhibbert

70 posts

48 months

Wednesday 19th April 2023
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The 6 cylinder diesels normally display signs when the chain is worn, a rattle from cold for a few seconds for example. It is rare the chains on these just snap without prior warning.

The N47 4 cylinder units can go noisy beforehand but they have a propensity to just snap without any signs of wear and then its a bit of a lottery regarding how much damage is caused.

I've had several 730d/640d BMW's and always buy cars that have been serviced more regularly than the 18k that BMW recommends. I've always changed the oil every 4/5k miles in my ownership without issue. After a few 4k changes the oil often runs nearly as clean as in a petrol engine. Using oil flushes is a bit controversial, if the history is poor then there is a risk of dislodging some black death to the oil pick up etc.

I think BMW say 9 years or 90k and then change the chains? A lot of people will say the chains should last the lifetime of the car but there is definitely an official recommendation by BMW regarding renewal.

As units age its not uncommon to alter the service schedule, Ford changed the Zetec timing belts from 100k to 80k for example.

Edited by dhibbert on Wednesday 19th April 18:45