Well we finally caught a break on weather today so after I got home from work I started working on the truck. The sealer had about 3 full days to cure so I expected it to be nice and water tight. I hooked everything back up, fired up the truck, and it still leaked. I couldn't believe it! Shortly after trying to find how it could possibly be leaking, I discovered a loose hose clamp on the heater hose directly to the left of the thermostat... I'm a moron. I don't remember loosening it while pulling the thermostat the first time, but I must have. After tightening that back up and putting everything back together, I started the truck up and the leak was gone. I ran the truck for a bit and while the heat is definitely much improved, it still seems a tad low. I'm going to flush, fill, and do a proper burp on the system this weekend as I'm sure I let a ton of air in throughout the process. If that doesn't bring the heat up more I'll probably flush the core, and hopefully call it a day!

 

Glad to report my heat is now fixed and blowing hot! Earlier today I got around to flushing the heater core. One of the hoses was brittle and split when pulling it off, so I got some new hose at the parts store and replaced it. I flushed the heater core thoroughly both ways and multiple times. I caught all the gunk that came out with a water jug and it was filthy and very dark gray in color. After that, I also found the cause of my temp gauge showing low. While removing one of the heater hoses to the left of the thermostat I went to unplug an electrical sensor for more room. I then discovered the plastic top of the sensor popped right off and was broken. After checking the service manual I found it was the Coolant temperature switch/sender. I ran to Autozone first and bought one, but after comparing with the original the threading and length, found it was too long. FYI The part from Autozone was a Duralast TU165. I then headed over to Advance Auto parts and got a correct replacement which was a BWD WT427, and it fit perfect. After putting everything back together and tightening it all down, I flushed the whole system 3 times with water, which removed even more gunk. I filled it back up with coolant and all is well. Thanks to all for the advice and help! This board has been an invaluable for all my repairs so far.

 

Mine blows too hot but doesn't run hot or overheat. But, it's a dragon in there on full blast.