While fuel can wash down a cylinder wall, as you say, that is a different issue. I agree that this would make it worse in a cold engine, but that problem hasn't been a factor for years, since emission regulations began to apply to cold start cycles (assuming proper operation, not malfunction)

Electric fans are better than simple viscous fan clutches, but we have had electric fans for 20 years now.

The accelerated engine wear is due to parts not fitting since they haven't warmed yet, in basic terms. While modern synthetic oil is still flowing, the boundary-layer lubrication depends on close tolerances between mating surfaces, IMO. That is why the instruction to drive at moderate engine loads, so as to reduce crank and rod bearing wear, and to a lesser extent, cylinder wall wear.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue