From what I have seen and come across in researching this problem on this very vehicle, I have found that the most likely and unfortunately common cause of this problem is the intake manifold gasket. It is so common infact that I have found manufactures of upgraded gaskets to counteract the OEM replacement, which was also supposedly beefed up to address this problem. You probrably want to have a pro do the repairs, as it is rated at an 8 hour job. That is if you can afford the 8 hours at their shop rate.
If your Ford Aerostar is overheating and losing water, it may be a bad radiator. You need to take your car in to get serviced.
Sounds like a leak.
You need to have the cooling system pressure tested.
have the head gasket replaced
Could be oil mixing with antifreeze indicating a bad head gasket Are you losing motor oil?
Its a strong indication of a blown head gasket
You may have blown a head gasket, check you oil to see if the antifreeze is leaking into there.
I have this same problem and it seems I have a bad manifold gasket. I keep losing antifreeze. This is not a cheap fix (for me)...around $800-900 because it's apparently very labor intensive. You may want to get yours looked at to see if you have the same problem.
check your oil to see if you have coolant in it. if you do your intake gasket needs changed.
When a Hyundai is losing compression in its engine the car will not run properly. Symptoms of low compression are misfires, stalls, and overheating.
The window motors could be losing power in the 95 Century. Check the wiring and switches for any loose connections causing the problem.
Assuming you have not noticed and leaks or puddles near the car the next thing would be to watch for steam coming out of your tailpipe. If there is you probly have a bad head gasket.