If there is no external leak and you know you are losing coolant, and you have established that coolant is not getting into the oil, then the leak must be internal, and on the combustion side. 95-98 Series II engines are prone to intake manifold gasket failures and burn-throughs which can send coolant into a combustion chamber. In that case, you should be able to see some white smoke out the exhaust or smell the sweet smell of coolant at the exhaust pipe when the car is running, especially just after start up.
Sometimes external leaks only occur under pressure. You can have a shop pressure test the cooling system to help you find the leak.
If the leak is internal and it is bad enough, it can destroy your engine by filling a cylinder with coolant. Upon start-up, the engine will try unsuccessfully to compress the coolant and instead will damage a piston, connecting rod, crankshaft, and/or starter. Most of which will be very expensive to repair.
It is not a good idea to ignore this problem. I suggest you do a pressure test to help locate the leak.