[Towncar]

Squeal can be alot of things.
1) Bad Belt, mis-aligned belt, loose belt.
2) Bad, Belt tensioner bearings.
3) Bad, Alternator bearings.
4) Bad, Battery causing alternator/belt overload.
5) Leaking coolant on the belt, causing slipping/screaching.

Maybe it's not engine related:
1) Disc brake, pad wear sensor rubbing on disc.

With all the engine related noises you can use a listening device (like a stethoscope, long screwdriver, etc) to find the source. Changing engine rev's while inspecting should help narrow the field.

How many miles are on your Conti? Is this one a 4.6L V8? You don't see any flluid leaking or spots where you park? How's the engine running, real smooth or a bit rough? How's the idle, smooth? Is there any sign of coolant in the oil?