I just replaced my thermostat it was stuck open, when I put everything back together it started leaking so I took it apart cleaned everything real good and put a good bit of rtv on both sides and put it all together. It looked good so I've been driving it around and to and from work for the past couple days but when I looked at it yesterday I noticed a teeny tiny little bit of coolant on the rtv. It's not dripping or going anywhere but I can take my finger and rub it along and I get a little coolant. My coolant reservoir hasn't gone down at all though and it's not dripping. I already ordered a new gasket and housing in case this is cracked. Do y'all think it's fine or should I just do it again

 

Cast aluminum cracks pretty easily. You could have a hairline crack that you can see, but the coolant found. The housings are cheap, so I think you made the right call to replace it.

 

SIlicon shrinks a little as it cures so I like to use a thin skim of silicon on the gasket, install the housing with the bolts lightly snugged up. Wait a bit for the silicon to firm up, then torque the bolts, than wait until later to fill and warm up the engine.

 

I recently replaced mine (along with the rest of my cooling system). Check to make sure the gasket surface on the housing is flat.

I always "lap" mine on my table saw with some 220-ish emory. Then a little sealant on the block to hold the gasket in place while i wrestle with the thermostat to keep if from slipping out of the recess.

 

I like to use FelPro gaskets instead of supplied paper ones for this and the water pump.
With no gunk as per there website.
Doing the thermostat without gunk can be tricky to keep it from slipping out of place, and possibly cracking the housing when you torque it down
in case you did not notice, but it can be done.
Make sure that channel the thermostat sits in is really clean along with the rest.

 

Before you unbolt anything, try cleaning it with water really well. Antifreeze doesn’t really dry/evaporate so confirm it’s clean and dry and then if you know it’s still leaking I would just do what’s suggested above.