None of these symptoms are what you want to find. Any car mixing its coolant with its engine oil has some kind of internal failure (often a head gasket failure) and a car that is consuming oil at a fast rate is also probably suffering some kind of internal damage or wear. Have a mechanic perform a few basic tests on the engine (compression, leak-down and head-gasket) and proceed from there. But if it's as bad as it sounds, you could be looking for a new engine (or a new car). These engines were known for being quite complex and perhaps not as durable as they should have been in some cases. They're also quite expensive to rebuild and may cost more to fix than the entire car is worth. At that point, you have some tough decisions to make.