I want to change the coolant in my 1987 560SL. I know how to drain the radiator, but I understand the block needs to be drained as well. The service CD indicates there are two drain plugs on the block--one on each side of the engine, near the motor mounts. I'm not sure I've properly identified them. I see two possible choices--a 17mm bolt that threads into the side of the block, or a 6mm hex socket that screws into the block. Neither looks to be very accessible. Anyone know for sure where the plugs are located? Appreciate any help....John Downey

It's the 6mm hex heads- the ones that point straight up. Don't take a bath getten them out . A long allen wrench is helpful. Do not remove the 17mm head bolts in the side of the block, bad things can happen.

Shooter: Thanks for the quick response. I kinda thought the hex head bolts were the ones. I tried to back one out last night but it was really tight--thought I would post a message and verify before breaking it loose. Looks almost like an aluminum plug--sure hope it isn't seized. I like the hex bolts when they are get up around 10mm or bigger--have a hard time getting necessary torque on the smaller ones. Guess I'll get after it today. Thanks again. John Downey