I have coolant leaking from the inside of the driverside wheel well? Is it coming from heater core?
I will assume you mean the left side when you state "driver's side".
If you have your model (230 SL, 250, or 280) in your signature it will help this and future question/answers.
On that side of the engine is the WRD with hoses and metal lines going to and from it that carry coolant. These should be checked.
Also, there are two coolant connections to the head on that side of the car (at least on my 280 SL there are).
If you still think it is, some how,
traveling from your heater core to your wheel well, you can remove the heater core out of the equation by disconnecting it from the system. (If you don't know what I am talking about, let someone who does do this.) You probably won't need your heater core for a couple of weeks while you are experimenting.
Good luck and tell us what you find.