I have a 2004 Dodge ram 1500 5.7. Luke warm heat

Check your fluid levels again. Sometimes air in the heater core doesn't get out right away. If fluid levels are good, try back-flushing the heater core. Good luck!

Sound like it could be a bad thermostat or maybe low on anti freeze or bad water pump. Does the engine overheat at all?

turn the fan off and let it run for 5 minutes then fan on. should be hot if it is and gets cooler as it runs the heat core is partialy plugged if not you have no circulation check the water pump circuit to heater

is water flou ower the heater you must let the air out from the radiator

I have the same truck, I have flushed the radiator both ways, flushed the heater core both ways flushed the engine four times, I have owned this truck for eight years and still cannot get it to heat up the cab. It will keep the windshield defrosted but that is all. If you find any tricks to fix this let me know PLEASE

THERE IS NO HEATER CONTROL VALVE ON THE WATER HOSES. NEW HEATER CORE. INLET LINE right before heater core hot, outlet after core look warm. Burped cooling system 5 times with engine at operating temp. Installed homade burp VALVE right after heater core outlet(high part of hose). Still no heat. Removed water pump, impeller still in good shape not stripped off shaft. Removed heater core hoses flushed water thrue the connections on the block to the water pump INLET and outlet. flushed water thrue heater core and hoses. Going to put it back togeter today. Used known good gauge to check water temp for operating temp in test. 195 f

did you use pure antifreeze if so remove it all and add a 50/50 mixture because antifreeze will not heat up good if its pure. needs water to allow good heat.

Why was radiator replaced?Did it have heat before ? If it was plugged, the heater core may also be plugged. Try flushing it with a water hose in both directions. I dont know why the botton radiator hose would be cold, the radiator should be a uniform temp and the air coming through the radiator should be HOT, when the engine is at operating temp. What condition was the old coolant? if it was rusty, the water pump may have lower flow than normal.

You may need to replace your thermostat. Also while you are at it flush and fill your cooling system.

You probably just need to backflush your heater core. You can use a hose to flush it back and then forward. You'll be surprised at how much sludge and gunk will come out.