I have a 2007 Dodge Charger. The heat blows out warm air. I have replaced the water pump and thermostat. When accelerating the vehicle, the heat turns to hot. Is this normal, perhaps a speical feature? I have 66,000 miles.
I’m assuming your car’s cooling system is verified to be filled with clean coolant to the proper level and isn’t leaking. If not, check that first. This symptom would usually be caused by a bad thermostat. But you replaced it? hmmm … well, the new one could be bad too. It has happend to me before. When I put in a new thermostat now I always test it first, by putting the new one in a pot of water along with a thermometer on the stove and heating the water up and verifying it opens fully at the spec’d temperature. You could take it back out and try that I suppose.
Another idea, If you had any work done to the cooling system or had a leak and added coolant before noticing this problem, it is possible the cooling system wasn’t air-bled properly when put it back together and refilled. What does the temperature guage on the dashboard say? Is it the same as when the heater was working properly? Or different? Any other driving differences you notice? That could be a clue. A faulty heater control valve is possible, but seems unlikely given the symptoms you report.
Oh, one more question: Why are you concerned about the heater now? It’s almost the 4th of July!!!
The coolant level is right at where it should be. No leaks. The thermostat was tested and all hoses are hot (fluids are flowing.) No bubbling noises or vehicle overheating (not improperly bled.) I want this working because I paid good money for this vehicle.
If it is a 5.7L you have to remove the beed plug above the thermostat housing to get the air out. If you car has the 3.5L engine I have found a number of cars with restricted oil cooler heat exchengers. The heater return line flows through the oil cooler near the oil filter.
I have the 3.5L…
could it be a plugged heater core, and when i accelerate this in turn forces the heat?
After the coolant leaves the heater core it must pass through the oil cooler. I have worked on several that others had replaced random parts; (heater core, thermostat, blend door actuators) and the problem is always due to a restriction in the oil cooler. If you remove the outlet hose from the heater core and start the engine you will witness good flow (leave the radiator cap loose so the system can vent).
The source of the problem is poor coolant causing corrosion/sediment.
From a Chrysler memo;
If diagnosing a complaint of no interior heat on an LX 3.5L vehicle equipped with an engine oil cooler, verify coolant flow through the engine oil cooler prior to replacing the heater core. If coolant flow thru the engine oil cooler is restricted, replace with p/n 04892259AA
When repairing any cooling system component, please flush and fill the cooling system with fresh coolant according to the procedure in the service manual and add 1 bottle of Mopar Coolant Additive when complete, p/n 68029698AA.
@Nevada_545 … interesting. I’m sure you are correct as you have experience with this engine it sounds like. But curious for more info. Do you mean that the heater core and oil cooler are in series? Seems weird b/c if the heater is turned off, then there would be no coolant flow to the oil cooler. Or are there several sources of coolant for the oil cooler, the heater core being one of them? In that case fixing a clogged oil cooler seems like it would be important to fix asap, as it might be inihibiting cooling other components.
Ah, if only we could return to the days of the air cooled VW Beetle! What a simple mechanic’s life that would be …
If its not the oil cooler, then try a new radiator cap, especially if the gauge goes up when going up hill. BTW, since it is July, are you running the Ac while testing the heater?
Yes GeorgeSanJose, the heater core and engine oil cooler are in series. The coolant flow through the heater core is never switched off, there is no heater control valve. Chrysler last used a heater control valve in 1992.