Smaller... it moves water faster AND the fan faster. It simply overdrives the pump by a few percent. MB redesigned it for a reason. The plastic fan is lighter weight and should be more efficient due to less mass. Ever put bigger wheels/tires on a vehicle and made it slower? Same premise here. Forged rims versus cast are lighter and have less rolling resistance. The aux fan grew vastly as the early one could barely keep up, 1990+ W126s received DUAL aux fans even to further improve performance. You may want to check the EPC to see if MB changed the crank pulley too.

BMW had same issues on the M30 six, A/C condenser tubes became smaller to increase surface area to dissipate heat, the fan blade was redesigned a few times, smaller water pump pulley (faster fan speed and water flow), different thermostat housing for more even cooling, and even a different crank pulley to overdrive the A/C compressor at idle for more performance.

My climate is horrible, humidity and heat. Every little bit helps.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]