Friday I flushed and refilled the Daks (45,000 mi.)cooling system which took about 2 1/2 hours! I just couldn't get the system to give up all the old coolant easily at all. I've never had to go to these extremes before with flushing a cooling system. What is the trick to doing this quicker? Granted it isn't something that has to be done often but 2 hours before I am happy that all the old coolant has been evacuated and the water stream is running clear seems a little long to me. It's a 3.9 which is just a 318 with 2 cylinders lopped off and I've never had this much trouble flushing a small block before.