I am not sure about the W116 but on mine they look like regular fittings, similer to what you would see on a Volvo excavator. It doesn't matter what the oe fittings are anyway have them replace the hose and put on metric threaded fittings. Then go with an aftermarket cooler. I wouldn't eliminate the oil cooler it is probably the best thing MB put on that engine. With mine I can't even holf my hand on the intake line but the outgoing line is cool.
If your cooler is leaking that badly I wouldn't drive the car until it is fixed, it could ruin your brakes on that side not to mention the horrible mess.
