I am still having heating problems with my 98 ram, i have again replaced the thermostat, found the previous new one sticking open, as well i have replaced the rad cap. top up fluids, ran truck to temp. checked rad level topped up level. ran again to verify no air locks. the temp guage only gets to about 75 degrees celsius, the top rad hose and heater hoses are hot to touch, the water in the rad at the rad cap side is very cold still. i hooked my obd2 reader to truck while it was running, the water temp is only getting to about 187 farenhiet while driving, ny thermostat is supposed to be 195. any ideas???? i am thinking my pump is hooped, any other suggestions I should try, as well is there a bypass on the heater core from one side to another in case of blockage. my heater hoses at core are both hot but thought maybe the core itself is blocked farther down.
Thanks tvindivo

 

Was the coolant dirty when you changed out the thermostat?

 

not at all, very clean looking

 

I would take the hoses off from the heater core and flush water through it to see if anything comes out. When you switch from heat to cool do you hear the blend door switch?