I think people are getting excited over very little.
If it was a more of a common problem (engine failure) I would be concerned.
All man made things can fail.
An engine failure can be caused by many things, build error, bad fuel, fuel type and the list goes on.
The guy who's engine failed was in Germany and some one else has supposedly heard of two Hilux's dropping their guts somewhere in Australia
There was mention of a leaking injector that may of caused the failure.
I would expect a PO0093 or similar fault code to be present from the ECU, it relates to a large fuel leak.
I would expect with the number of D4D's with this so called knock or rattle when cold that there would be a lot that has failed but it seems not to be the case.
I'm sure if you looked hard enough you would even find a BMW engine that has failed....and they are the best engine builders in the world.
Caterpillar, Detroit and Cummins all have the odd engine failure but then also there are many of their engines that have done in excess of 1 million kilometers with very few issues.
Hell I think I'll take the 2 month old Hiace we have with less then 2000 kilometers back to Toyota because that has made this noise form day one.
I might do the same with the Hilux as well.
If it was a problem I'm sure Toyota would address it very quickly...there was comments made that they know about it but didn't want to do anything until the vehicle was out of warranty...after then the customer would have to pay for repairs.
I don't think a vehicle manufacture would be that stupid to think that as word would soon get around, there would be no resale value n the second hand market and people would not by a Toyota again.
Do you really think Toyota would gamble with their reputation regarding being the "builders of very reliable vehicles".
Seeing this engine design has been around for over 8 years and the current 3lt. D4D has been around for over 4 years I think they would of rectified the problem by now if it was a reliability issue.
Seeing most D4D's do it I doubt Toyota See's it as a problem, may be a noise problem but not a reliability problem.