I got my coolant housing and hoses replaced about a month ago + a flush. All new fluid is in there. However I'm looking to put in a 180 degree thermostat this week. Do I still have to drain the bottom hose out too while I do this too?
Similar to this video; he explains he didn't drain the bottom hose because it already has new coolant in it.

 

Draining does not imply discarding the coolant, if that is what you mean. Just collect and reuse.

 

I recommend switching to Extinct's inline mod instead. You can put a 180 degree unit in the housing, and you eliminate the ridiculous OEM setup with its failure-prone plastic.

 

I second this. Mines installed and I'm VERY happy. Also if the thermostat fails on a trip every parts store on this continent will have a thermostat for you on the shelf.

 

Third. In line thermostat is the first modification I make to all my Discos.

 

I’m in New England. How much of an adverse effect on cold weather warmup with the inline mod?

 

Agreed. I collected the coolant when I had to change the water pump not long after swapping coolant. I filtered the recovered coolant through a couple layers of paper towels and reused it. No problem doing that.

 

I’m in the PNW, so comparably mild temperatures but I would say it takes no longer than 5 additional minutes to get up to full temp. Totally worth it (in my opinion) for more stable temps.

 

Living in central Indiana and temps summer/winter can be anything, usually ridiculous! Lost 1 engine to an overheat, on this new one, I installed Extinct’s thermostat mod.

I’ll let you know about warmup, but if it takes a bit longer, no worries. Better than an overheat problem. Plus I have a block heater so when it’s really frigid, I’ll plug it in.