BobinOH: This might be a silly question, but if you run the engine long enough to bring it to operating temps, but not long enough to 'burn' all of the coolant, how does the remaining coolant look in the reservoir? The reason I ask, is because when I first purchased my 240D I noticed the coolant was a milky brownish-green. I suspected that it might be cracked block, but after replacing the coolant, I ran the car for over a year and it remained clear and bright green. I am curious to hear more about your case. I don't know anything about the TD's. Is the oil cooler and radiator one piece or two?