Could be the levers. A family friends shop in upstate NY has seen some N62s back in his shop every 2-3 yrs after the inital lever replacement, they always return after a drop in temp. This info is what drove me to the "last of the M62s" when I shopped for my E53. Normally when I purchase a used vehicle, it's ALWAYS the final year of production for that platform, the dreaded N62 lever issue stuck me with the '03 MY E53.

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'03 X5 4.4 Sport, last of the M62s (8-03 build date)
I believe in deadication to craftmanship in a world of mediocrity!