electrolisis, bad head gasket, bad radiater
If a 1999 Dodge Intrepid timing chain goes out a valve in the head can easily be damaged.
it is on the intake behind the alternator. :) look between the thermostat housing and the heater hose that goes to the top of the intake. it is right in that area behind/under the alternator. it has a small 2 wire connector that goes to it.
"Does the top or bottom heater hose from the firewall go to the water pump on a 1991 Dodge Dakota V6?" The top heater hose from the firewall goes to the water pump and the bottom hose from the firewall goes to the top of the block where the temperature thermostat housing is located.
5w30 or 10w30
could possibly have a rodent or rodent nest inside the heater box.
4.5 quarts
Back of the trans, in the housing that the passenger axle goes into.
Thermostat housing
If the engine is getting up to normal temp, the heater core might be plugged. Heater core is not plugged and normal operating temp!
There isn't a water control valve on a Dodge Ram. The heater core gets full flow all the time, the amount of air inside the HVAC housing that goes through the heater core is what regulates output temp. That airflow is controlled by a blend air door.
this goes for most any car or truck you will loose having heat in the winter
It is the connection between the lower radiator hose and the water pump.