05 S4 100k miles. Scary?
 

So i found a VERY well taken care of 05 S4 w 103k miles. Assuming I get to dealership tomorrow and they don't have any idea if timing chain was done should I just walk away? Is the problem common enough to where u just shouldn't buy one if there's no proof it's been done? My 1st S4 so not sure what I'm getting into here.

It's a hard one. I bought my S4 with 80k miles on the clock. Always had the 1 second normal chain rattle at start up and had a full service history with no expense spared. My car always ran great, but ay 115k miles I started to notice the chain rattle on warm engine restarts. 2 weeks later and the dreaded over advanced code popped up thanks to a broken chain guide. Had the timing service carried out, New chains, tensioners and guides etc and clutch and flywheel at the same time. Cost me just under £6000 GBP to get it back on the road.

So it really is a tricky one. Some people have reported chain guide failure at 60k miles, others have reached 150k with no issues. If you want an s4, ideally get one that has recently had the chains serviced, or at least be prepared for a large bill as and when you get them done. Even if they have already been done, if the oil changes are neglected, that can cause serious premature wear on the components and ultimately cause guide and tensioner failure

The timing chain guides and tensioners are really dangerous in the 4.2. Plus many of the plastic/rubber parts involving the engine seem to have a design life of 9 years/ 130k miles.