Mine was replaced under extended warranty - after they replaced ~8 or 10 #2 glow plugs
final proof was pressurizing the radiator overnight and the next morning there was antifreeze on the GP.....
check with GDE about the issues - they haven't mentioned a head replacement - but they're really up to date on potential problems (main one is probably getting everything aligned properly)
It did sound like head gaskets have to be the correct thickness - I think there are 3 or 4 variants depending on how the rest of the assembly measures
_________________
2005 CRD
stuffSkeptic quod gratis asseritur, gratis negatur