okay, i understand what you meant, but are saying that when the aux fans are on and the engine is running, it doesn't cool down? also, i would think the cut out point should at least be below 100C. in the m104 engines 106C is when fans cuts in. i had a crazy overheating problem like yours more than 20 yrs ago with a mitsubishi four banger. when it was running normal, everything was fine but when it ran hotter it quickly went into an overheated state from which there was no recovering. my mechanic opened up the head for a look see (easy in those simpler designs) and saw that it had higher compression dome head pistons which was a late model changeover. the higher compression sorta explained the higher temps and to make a long story short i finally went and got an oversize radiator. that took care of that. my point is that your description of the overheating behaviour reminds me of that case and maybe your radiator is indeed plugged up and not providing sufficient cooling. BTW, remanufactured Behrs are available for about $125 - could save you some money. (resedaradiators.com)
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"