My 1994 Renault Twingo will start, and it will run as long as I continuously press the accelerator (even just a little). Enough oil has seeped out of the engine to cover the lower half of the block. The last time I drove the car, the engine kept overheating and it was leaking coolant. I also noticed that the oil is over-filled. I know that I have to find and fix the coolant leak, but I have a few related concerns:

1. What is the likely cause of the oil leakage (e.g. blown gasket)?

2. Is this normally a stand-alone repair, or is it often accompanied by other repairs (e.g. damaged piston rods or heads)?

3. I realize the required repairs could cost between $200 and $2000, but what are some reasonable cost estimates for these repairs?

I'll provide more information, as needed.

Also, I live in Germany and things are quite EXPENSIVE here, so I'd like to get a headstart before going to a mechanic.

Thank you.