I've known about this fault for some time here in Australia..no class actions or recalls that I'm aware of. The problem has started to occur intermittently on my cooper s and was quoted $1700 to replace chain etc. I don't drive the car hard and always warm her up before take off.. what is the danger of continuing to drive with this issue. Thanks for any advice.
Vincent

 

Timing chain and tensioner is a well known problems with N14 engines. It needs to be addressed sooner rather than later.

Open the valve cover and see if chain's plastic guides are still intact. If they are broken (the chain is slapping around enough to tear them apart), it may be close to skipping a tooth and introducing your valves to the pistons. If the guides are still intact, you could start by replacing just the tensioner, but that's unlikely to quiet the chain if it has already stretched. Still worth a try.

$1,700 is about right to replace the chain and tensioner.
You can DIY it, but need a few special tools to lock the cam shafts in place while you swap the chain. Depending on your level of confidence in your own wrenching skills and how many tools you already own, you may end up saving $~1.3K by DIY-ing.

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