The very first thing to do is check the vent on top of the differential and be sure it is open and can vent. This will cause pressure to build up and leak from the weakest place. Clean the rear end down with some brake cleaner and drive it a few days and recheck for a leak.
Find the source and repair it.
best thing to do is buy a rebuilt one
That depends on where the oil leak is, is it in the motor self or is one of the seals leaking?
you shouldn't have to change them unless they are leaking, blown, or you take the heads off for a repair or rebuild
Where is it leaking from? Oil pan, intake, valve covers, oil cooler lines? welding
If coolant is leaking inside your cabin, you have a leak in the heater core. The only repair is to replace the heater core. Most auto parts stores sell them.
The sunroof on a Chevy Cavalier can often be repaired by replacing the outer seal. This prevents rain from leaking into the vehicle and causing additional problems.
where is it leaking from?
replace or repair. It will only get worse.
your heater core is leaking
usually caused by a leaking heater core.
its the PCV valve