Do I have to drain coolant before head gasket change? (2000 Dakota V6)

most of the coolant should run out when you disconnect the lower hose. There is no drain plug on the block for anti-freeze unless you remove a freeze plug which you don't want to do.

Actually, some block DO have drain plugs. My 318 Dodge engine is one of them.

But you dont need to drain any further than you have already done. The lower radiator hose is sufficient for this kind of work.

It never hurts to check the Welch plugs ("freeze" plugs) occasionally. If these start to leak due to corrosion, you need to tap out the old ones and install new. These are one of the common causes of coolant loss that is hard to spot, mainly because they are seldom checked. In an ideal world, these plugs last a long long time, but if people havent maintained their coolant, havent kept the cooling system oxygen free, they can rot out in a hurry.

I think there should be a drain plug on each side of the block, between

If there's not a plug in the v6 casting for some reason, don't sweat it. When you lift the heads off, a little bit of coolant may gush out, but not a whole lot. If it falls into the cylinders, just wipe it out with a towel.

If you do find the drain plugs, the chances are about 10:1 that you will never get them out without an acetylene torch. I drain blocks after I pull the heads using a piece of 5/16 tubing as a siphon.

Nah! No need to drain the coolant. In fact, when removing the heads make sure you get as much coolant as possible into each cylinder. It will prevent rust and corrosion while you have the heads off.

If there is not enough coolant to protect all cylinders you can substitute window washer fluid or brake fluid. With summer approaching, grass clippings from the lawn would also be a candidate. Good luck!