How do I tell if my rear main seal is leaking in my 96 Buick regal

SOURCE: water leak internal on buick regal gs 1998

there is a drain that must be plugged . it drains the condensation from the evaporitor on the AC system. these need to be cleaned once in a while. look from under the car around the firewall . you will see the tube. stick a wire up it to clean it out. and it will dry up.
good luck paul

SOURCE: replace rear struts 1996 buick regal

Here is a link describing your strut replacement. Autozone also has free tool rental for the strut spring compressor if you need it. Thank you, and don't forget to vote. http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152800681ba

SOURCE: hood latch & cable broke in a 96 buick regal

You should be able to pick up a used one at a junkyard for less than $20

SOURCE: 1996 buick regal 3.8L. Rear brakes loud thumping

Check for leaks in the brake lines and calipers or brake cylinders. If leaking have it repaired right away its not safe. Change the brake fluid, take the old fluid out add new fluid or have it professionally done.

SOURCE: 98 buick regal ls - po442 obd code

Usually the source of the leak is the gas cap (either loose or defective) but if that doesn't apply to your issue then the canister is next to the gas tank.