I will be replacing my thermostat. I watched SteveNYCNewYork on youtube removing the bleed valve from the new thermostat in order to maintain a trickle of coolant at all times. Is this suggested for someone like myself in Phoenix heat/cold?
The bleed screw is basically a loose rivet of sorts. It loosely fits in the bleed hole to allow a "trickle" at all times especially under pressure until the TS gets to operating temperature which can be anywhere between 165* to 215* depending on make and model of the vehicle. No need to remove it and to do so is actually rather silly. The benefit just isnt really there to be honest. If anything, TOTAL removal would be a benefit in summer months but again, may not be right for the application or use.
If your vehicle is stock, isn't used for much other than point (a) to point (b) or milder use such as outdoor recreational use, replace with stock temp and call it a day.
If you're a bit harder on the truck and its modded fro more abuse then I'd start taking a bigger look at the entire cooling system as a whole and modding it with a 2 row radiator from a Super/Charged version, maybe do a 180*-185* TS, Consider if not already equipped with an E-fan upgrade rather than a clutch fan or constant velocity fan (doubt you have one of those), and replace all of the coolant hoses with a pure silicone hose kit like Samco or similar quality hoses and keep yours on hand for spares should you need them on your offroad adventures in your spare parts tote.
The addition of running a good premix solution has its advantages as well additives that can reduce coolant temps by 10*-20* can also help.
This way you're making a substantial cooling system upgrade with a higher cooling capacity, better flow characteristics at a lower temperature keeping under hood temps down. The truck will get a little better gas mileage, Nothing you'll get rich off of or be able to make a large contribution to your college fund unfortunately AND the truck will run a lil better.
Keep in mind now tho when doing that, if you get into really colder temps, the truck could be slow to warm up but unless you're enduring 20* temps. Should be much to worry in AZ.
I live in Vegas where 3 months out of the year its 118* here all day and night even after the sun goes down and' Ive made same upgrades to all my trucks. The 2013 Xterra will be no different.