stuck open? no great effect unless you are in a cold climate. In that case you won't be able to generate enough heat for the cabin.

 

Thermo is least of my worriez car is geting hot after 3 miles im losing water but no present leaks so the oil was milky so im thinking head gasket idk when i crank it white smoke comes out ! So i put some head gasket sealer in and changed oil its been about a week and oils still clean but before i did that my wife was driving it and no problems till bout 44 mins into drive and car got hot and shutdown it blew out coolant hose coming from loop going towards back of motor ever since then it wont drive far at all no more water loss or dirty oil but overheating!! I looked at waterpump and it looks solid so idk i replacrd fan clutch a month ago and also drive shaft!!! I cant really afford another problem is therw a cheap fix to keep me rolling im poor and this is my only ride

 

You probably have air in your cooling system. Search this forum for guidelines on how to bleed it.
This is not the truck for you if you're that short of funds and can't have it off the road long enough to replace the head gaskets.

 

sounds a whole lot like head gaskets. Sorry but it is not good news. If you DIY it'll be $500-700 when all is said and done. At a shop you're looking at $1500-2500 depending on your location.

 

yea im just gonna sell it ! Sucks its a nice vehicle