need more heat

My 98 D 4x4 5.9l needs more heat output. I changed/flushed out the coolant hoping this will increase the heat but about the same. Need heat in front and back.... Any ideas?

Try putting some cardboard in front of the radiator to block some of the airflow. If that improves your heat, you probably need to change the thermostat.
Dave

Try putting some cardboard in front of the radiator to block some of the airflow. If that improves your heat, you probably need to change the thermostat.
Dave

Replaced my thermostat to a 180 stat and the gauge shows around 180. It was showing the same before the replacement. Shouldnt it be in the middle of the gauge for normal operating temp?? Its at the 1/4 mark. With this new stat it only heats up to 180 degrees, thats it?? I was reading some posts talking about a 195 stat and now Im wondering if I should of replaced with a 195 stat instead. Is could be just my temp sensors or a bad gauge.

code3
Apparently there are two strings going with your discussion about heat. Scroll further down the page and find the thread "180 degree thermostat", started by bljseal for more discussion and suggestions.
I wouldn't put much faith in where the needle is on the gauge, but if the heating system is working properly, the air coming out should be hot enough to make it uncomfortable to hold you bare hand in front of the outlet.
(And BTW, yes, some of the possibilities are bad sensor or bad gauge, but read the other post and try some other things first).
Dave