Motor cock.

Hello,

I wanted to drain the coolant from the motor block via the two screws
next to the transmission line, but nothing was coming out of there? only
black goo was inside. I started the car and sill nothing out of there. I
am sure I opened the right two screws. So what is the problem?
.
thanks for help.

so what do you think?
cK
1972 280SE 4.5L