Same exact thing just happened to my 91 GL with 100000 miles on it. The chaNGE
IN TEMP ALLOWS THE GASKETS TO EXPAND AND CONTRACT WHICH CAUSES THE HAEDS TO
LEAK. yOU ARE JUST STARTING TO LEAK SO CHECK YOUR COOLANT EVERY COUPLE OF DAYS
AND YOU SHOULD BE ABLE TO DRIVE ON IT FOR AWHILE. I decided to not fool witht
the stains on my driveway and get it fixed. $800 to replace all rubber gaskets
in the heads. Good luck