Was the Silao Mexico plant not making all previous gti engines? I.e. is it a design issue, or a manufacturing issue?
What tolerance stacked up caused the problem? I.e. dimensions of what components were causing low oil pressure?
If the problem is with the oil pressure in the vanes of the cam adjuster, and it wasnt fixed by heavier weight oil, assuming its leaking through these tolerances, was the ecu programmed to alter the solenoid to compensate, or was the idle reprogrammed to just retard the timing enough not to overlap the exhaust valve? Were the tolerances for all engines assumed to be represented by the lemons bought back? Does the new oil pump generate less pressure and this is more of the reason over tolerances?
If it's truly tolerances that's the root cause, and I assume the tolerances are outside acceptable limits, how did this pass vw QA?
Is there an adverse and potential long term reliability effect of both valves allowed to be open at the same time?
And finally, why do we believe that the engines power output is not negatively affected, is it retarding timing enough???
Most probably there is nothing to worry about as the cars are fast enough, and dont make any nasty noises. I just get irked if engineers blame manufacturing /qa if it's really a design problem.