Looking for coolant drain bolt on M103 block?

I can't seem to locate the block drain bolt on my '91 300E (M103 engine).

I need to drain the ENTIRE system to flush, due to the ATF in the oil issue I have recently repaired.

Could someone describe to me please where this drain bolt is located?

Thanks!

~~Iodyn

Also, I just received the MB degreasing agent and citric acid powder as I was typing this. They both come in powder form but don't explain how to use it. Should I mix these agents with say, 1 gallon of water, then pour into radiator? Certainly I wouldn't pour the powder in without mixing it with another solution would I?

Thanks for your help....

[Mike Murrell]

Looking at the engine from the front with hood up, go to passenger side. Just underneath exhaust manifold, in between cyl 5 and 6. Look for drain plug in this area. 19mm socket takes it out.