Since I drained to replace my heater core I thought I'd use some superflush. I topped up with tap water, bled and ran it, drained again (the water was still awfully green), poured in the superflush, and filled again. Now I'm in the process of running that.

Here's my problem. When I pull the radiator drain plug, I only get about 6 quarts out. My '84 L69 has a 17 quart capacity, so I'm only draining approximately 1/3 of the system. After the 2 drains, I figure I have about 45% old mix, 55% tap water, and the bottle of superflush in there.

Even if I run a flush kit, the engine is full of tap water. How do I get it (mostly) replaced with distilled, and most importantly, how do I get a good mix? I really need a way to get more than 6 quarts out when I drain.

Unless someone convinces me that it's easy, I'd rather not mess with freeze plugs since I've never done that. Also, I just RTVd the thermo housing on with a new gasket, so I don't really want to undo all that again, but I will if I need to.

Mission Impossible? Could I hook a shopvac to a radiator hose? Any ideas? Thanks, and sorry for the long wind.

BTW, replacing the heater core wasn't too hard at all, except I got a crick in my neck and the pipes on the first replacement I got were too far apart to fit through the firewall. It looked like coolant may have been dripping down the firewall, so I'm not sure the original was even leaking, but as long as I had it out to mop up it seemed silly not to replace a $30 part that would soon leak if it wasn't already.

 

There are 2 plugs on either side of the engine block, a plug on one side and the knock sensor on the other. These drain the block itself. Located just above the oil pan rails.

 

Yep...when I drain my radiator, I need about a whole gallon of coolant. When I pulled the passenger side knock sensor, I needed another gallon. Never had to drain the driver's side.

 

After you get the plug out, replace it with a petcock to make it easier the next time.