my 4 door oldsmobile cuttlass

If it is leaking to the outside and puddling on the ground you have a bad gasket or a leaky hose connection somewhere. If the cooland level just goes down but doesn't show up outside the car it is an internal leak from a gasket or a crack in the block r head. External leaks from hoses or hose connections are easily repaired by replacing parts and tightening clamps. Gasket leaks, both internal and external can often be slowed or totally sealed up by adding Bars Leak to the cooling system. That's an easy and inexpensive solution that you can easily do yourself. The product won't harm your car and is available at any auto part store. Once you have addressed that, and if there is water in your oil you will need to change oil, maybe a couple of times to eliminate it from the crankcase.

Also forgot to mention the water pump. If it is worn out there could be coolant escaping from the seal around the shaft where the fan bolts on. Sometimes a bit hart to see so look carefully. The only fix for that is a new water pump which is not a huge deal. Get it done at an independent shop if you're not going to do it yourself. Don't go to the dealer for that, it will cost at least double there.