If you have one this weekend then do yourself a favor:

1. Don't screw around with the heater hoses and the block that goes through the firewall. Simply unscrew the retainer right where they go into the bottom of the heater core itself and replace the two O rings right there. If you have to mess around with the firewall block I recommend that you have a brand new one on hand just in case you break it.

2. On the whole coolant making a mess deal, drain the block entirely and then take a one gallon coolant jug (you know, the square ones) and cut the top and the front out of it. The idea is to cut it so that it has the profile of a chair and then you slide the back of the chair in under the pipes where they connect to the core. When you loosen the pipes all of the coolant will drain right into the jug. The first time I did it I was downright giddy it worked so good, not a drop on the customer's floor board.

Past that it is a really, really straightforward deal. I recommend a couple of blankets or a set of knee pads to keep from wearing your knee caps out as you will spend a bit of time on your knees if you do not have access to a hoist.

Have fun,
Mark