Only fitting in 3.5 gallons after draining coolant?

[Itsnotme1988]

Working on flushing the cooling system on my 97 k1500 and can only get about 3.5 gallons to squeeze in. drained from heater core and lower radiator hose and filled with bleeder cracked until a steady stream, then closed to finish filling.

Tried last night, gave up and drained today only to find still coolant mixed in (flushing with distilled after lots of water pushing through from a hose just forgot heater core. Pushed a good 15gallons through.)

Am I missing something?

[cjones]

Just drained and tried refilling in the 98 Sub and had similar results as I was expecting to refill with more 'fresh' coolant.

I think the problem you're up against is that the block is difficult/impossible to completely drain since the plugs are in a bad spot, therefore there will be more residual coolant/water in the block and heat core line then you think.

In my case I shoved a hose in the reservoir and cracked the upper radiator hose and then started the engine until I had no more green coolant coming out (not sure if this is recommended but it seemed to work). This did a good job of flushing out the old coolant, I then added concentrated Dex-Cool to fill up the system, ran it a couple minutes and then went back to ensure it was full. Hope this helps. Chris