Engine running cold

It's mormal for the lower hose to be cooler than the upper. That just means the radiator did it's job.
With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both hot to the touch. If not too hot to hold, then you have to look at the actual engine temp and if that is up, if it is, then your looking at a restricted heater core.
If you find that they are both too hot to hold, then the heat in that vehicle is controlled by a blend door that regulates heated air flow. it is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.
If they are both not too hot to hold on to, then you either have a restricted heater core or the system is not completely full and getting air pockets for some reason.

the temp gauge is only reaching 160 degrees or lower. both heater core hoses are HOT. I stated that I flushed the core already. Not restictions in flow. Lower hose isn't cooler its cold. After driving for 20 minutes still cold and no pressure built up in radiator and fluid inside is cold.

If the engine isn't building enough heat, there isn't much you can do about that short of covering the radiator and that would be dangerous.

? why wouldn't the engine build enough heat ? It wasn't that cold when this started so the radiator doesn't need covered.

It's a cooling system, not a heating system. The engine generates it's own heat and the cooling system removes it. Yours is just working a little too good. The thermostat is the only thing that has the ability to bring the temp higher.

How do I get it to work not so good so that I have heat ? And why isn't it reaching normal operating temp. It is only at 145-160. Will the thermastat open if it's only at 160 ? The thermastat is 190 or 195. Should I change it to a 160 degree one ? what's my next step ?

The ONLY thing you can do is install a 195 thermostat and make sure it's working. If the engine can't generate more heat than that, there's nothing you can do about it beyond restricting the air flow through the radiator annd I don't recommend that.

I did replace the thermastat twice and it is working. I tested it. why won't the engine generate more heat ? It has always reached 195. So what's causing it to not reach this temperature ?

Is the fan clutch possibly locked up causing it to pull too much air through the radiator?..

See the guide below on symptoms of a bad fan clutch

https://www.2carpros.com/articles/fan-clutch-symptoms

We Have a truck with this exact sypmtoms. Have replaced everything but radiator. Did you ever find a resolve for this?

It appears the original poster never returned to say if they found the problem or not. The only items that can really cause an engine to run cold are a faulty thermostat or a cooling fan that is pulling air all the time. If you are in a very cold environment a larger than stock radiator or running the heater on full shouldn't do anything more than cause it to take a bit longer to reach operating temperature. However a thermostat even slightly open or one that is faulty and opens at a lower temperature will cause it to not reach operating temperature at all as the coolant is constantly being cooled instead of being held in the engine to transfer heat.