I noticed a puddle of antifreeze a little bit ago...raised the hood on my 88 240 and the white plastic plug on the inside passenger side of the radiator was gone. The radiator was replaced in 03according to the sticker. Of course the plug is no where to be seen, I have never had an overheating problem. I'm assuming it is some type of expansion plug designed to come out under pressure...or maybe it vibrated out on its own??? I checked the Bentley and no mention of this type of plug...checked IPD and they don't sell a replacement plug. I bought the car 6 months ago so I have no history on it or the radiator. I'm a little befuddled about the whole thing. I do remember when I was cleaning the engine bay after I bought it, pulling on the plug and it came out very easily so I shoved it right back in when I saw green coming out...thought at the time I never saw anything quite like that before. I guess I'll check with the dealer tomorrow