Manager Forum

2003 DODGE R1500 4.7 SINGLE ZONE HEATER HAS NO WARM AIR FROM VENTS, REPLACED T/STAT, FLUSHED HEATER CORE 2 TIMES. ACTS LIKE AIR POCKET. ONCE IT BLEW OUT 120 DEGREE TEMP FOR ABOUT 3 MINUTES THEN ALL OF A SUDDEN TEMP DROPPED TO 72 DEGREES. NO PRESSURE ON COOLING SYSTEM LIKE HEAD GASKET PROBLEM.

First thing to do is check and see if both heater hoses are hot, if so, with it running turn the heat selector from cold to hot and see if any change in temp, if not, you need to be looking at the blend door or motor, or even the controls.

hey, welcome to the forum. like joe said check heater hoses. what is temp gauge reading? if temp gauge is where it should be and heater hoses are hot, i mean so hot you have to pull your hand off, well some people do. i have 3/4 of an inch of callous on my hands and if i grab something hot in the morning i don't feel it until noon. well anyway, if it's working out that way then your issue is in the heater box. either a blockage in core vents or blend door is flopping around. i've seen all sorts of stuff in the heater boxes causing temp issues. one the other hand if one hose is hot and one cold the core is probably the culprit. i've seen chunks of gasket goop stuck in hoses causing issues like this. make sure there are no restrictions in the hoses. keep us posted please.........

does this truck have crap on the dash? You might hear the door move. But there could be a pen, straw, barrette, french fry or something keeping the door ajar.

I have 2 clear vinyl hoses I can install inline to the heater core. Makes it real easy to see coolant flow. That's how I know whether there is sufficient flow or not. Hardware store has the hoses real cheap.

Real good tip ricmorin. One of those simple things that can save alot of guessing.

good tip ric ive never thought of that one. then again i could fill a library up with the stuff ive never thought of.

it's kind of funny. we all have little tricks we use that when we post them others look at them as "that's a f$#^&ng great idea". why didn't i think of that. another hidden benefit of sharing. it's like when i flush ot a heater core i have a piece of heater hose attached to an adapter that fits onto my wet vac. it contains the water that's used to flush it as well as adding the vacuum benefit. it holds 5 gallons and no mess to clean off the floor. i use it regularly when i'm opening up coolant systems after draining them. we all know no matter how long it sits with the drain open there is always that gurgle sound and splash when we open the system.