Reading the tea leaves
> How the hell could this flaw not show up in bench testing
> of the motor or road testing of the cars?
Keep in mind that the TDI was off the US market for a couple of years, during which time EPA Tier 2 rolled out, with its terminal lubricity agent issues.
So the CR was developed in Europe, using EU spec diesel, which is both higher lubricity and more consistent lubricity than US (ASTM) spec fuel. By the time the CR was sold in the US, it was a no-turning-back committed platform.
I'll bet VW did see some fails in EU testing, but odds are they were all obvious misfuels. Still, the consequences were much more severe than for earlier TDIs.
For VW to have seen what was going to happen in the US prior to the 2009 intro, they would have needed to have perhaps 100 test units afield here.
That said, had they had a large number of test units, what would they have done in response to the failures? Well, they now have vast numbers of "test" units out there, years worth of 'em, and they have not done anything obvious to address the problem, other than yellow decals. The decal campaign suggests some surprise on VW's part.
I'd like to get a new TDI, but will skip the CR generation entirely at this point, and wait for customer beta test results on the upcoming EA288.