I want to flush my coolant today on my 1988 420sel. I'm trying to find the radiator coolant drain and I can see two plugs at the bottom. One of them is black with three sections cut out and one of them is blue with an X in the middle.
I know I could just open them up and find out but I just had my transmission filled yesterday and I don't want to drain it.

Thanks for your time

Peter
1988 420sel
1988 300e

The blue plastic plug will drain the coolant from your radiator, but it will not flush the coolant from your system. Dont know on the 420 but there is probably an engine block drain plug that needs to be removed to get all the coolant out that is in the engine block. There are lots of posts on here about doing a complete flush.

Not sure, but vinamg's answer in this thread might work for you.

http://www.peachparts.com/shopforum/showthread.php?threadid=26322&highlight=drain+plug

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"