I drained the coolant as per the service manual for the purpose of flushing and changing. The service manual says all that is required is to remove the radiator plug. However, I only get 1 gallon out. The specifications say the capacity is 10.5 quarts, so I assume there is still a gallon and a half in the block and heater core. If so, is draining at other locations required to remove all coolant? If so, where? ....and why wouldn't the service manual specify? If someone wasn't paying attention to the quantity that came out after running water only for flushing, and added a 50/50 mix, the mixture overall would be less than 25% antifreeze. What am I overlooking?

John

 

You do realize that you need to remove the pressure cap to allow air in to the top of the system to get it to drain, right? Also, don't try draining it with the car parked on a sloping driveway. If you can get at least half the coolant to drain, then after flushing with water, you can add 5¼ qts of 100% antifreeze and you should wind up with a 50-50mixture.
Another possibility is to disconnect a heater hose and fill with antifreeze through the filler neck. As antifreeze goes in it will push water out of the hose. Stop when antifreeze starts coming out the hose.
When flushing, flush gently. Don't apply full city water pressure to the cooling system or you'll blow your water pump seals. Been there, done that.