thanks. the thermal runaway is understandable if there is insufficient cooling for the condenser. however, the engine fan seems much more powerful to me in sucking air thru the condenser than what the pusher fan could do. nevertheless, the engine fan alone may not be sufficient to cool the condenser for the ac to cool well esp if the car is stationary plus ambient temp is hot. i wonder why some other makes does not need a pusher fan (more efficient design for heat exchange?) and how one e53 owner could live with his pusher fan removed.