So I have a 87' 740 turbo with 78,800k. today I drove about 30 miles, it was about 90 degrees outside. Had the AC cranked, wasn't running hot at all. I got to where I was going and turned it off. Got back into it 20 minutes later and had pools of coolant on both the driver side and passenger side floorboards,I have no idea where to start the troubleshooting, any help in the matter would be greatly appreciated.

 

Post in 740 forum; my guess is your heater core let go..