Draining block

Here is the block drain location for your car.

If I use a uview 570000 antifreeze exchanger. do I still need to drain the block removing the block plug?

No, the fluid exchanger is supposed to do just that, exchange the old for the new so whatever is in the cooling system will be removed, even in the block.

The machine I have uses shop pressure to create a vacuum. But only seems to suck out 40 to 45 percent of total copacity. Then ii switch the shop pressure off and it fills with coolant at the concentration I mix. But I figure there must be water still in the block . What am I doing wrong.

I also have a good vacuum, no leaks, and holds.

I would just drain the block manually to remove the doubt and start from scratch, some of these fluid exchangers work better than others and I really like doing it old school way and just drain and flush manually, then fill it with 50/50 coolant and distilled water.

Thanks, that helps, machine was a waste.

No problem! I do things the old way, but it's a guarantee that it gets done right.