I have a 2000 Dakota club cab with a 4.7. I believe my heater core is a little restricted. When I felt the hoses coming out of the core one of them is defiantly hotter than the other one but I don't know if its causing this problem. when I am driving at low RPM the heat seems to cool down, but when I am at a higher RPM it seems to blow hotter. Even at high RPM the heat is still not as hot as it should be. could this be the result of a restricted heater core?

 

Welcome to the forum!

It could be a restricted core, yes. If you can remove the hoses you can reverse flush it using a hose and it may help some. Some temp difference is normal between the inlet and outlet hoses so you are flowing some water.

How's the engine temp? Thermostats can go bad but you'd probably pop a code if it was staying very cold.

 

I did reverse flush the core. before I flushed it I could hear what sounded like water running under the dash, but after I flushed it that sound went away. the temp is running normal, just below 210.

 

It still could be a restricted core. Flushing may not clean it out completely.

Another potential problem is that the water pump can become less effective as it gets older.

 

*nod*

When we pulled the water pump out of the stepson's Taurus (a 1999 model), the vanes were ... missing. They had corroded out with the previous owner's neglect.

When we did the water pump on the Dakota (1988 w/3.9L), the vanes were eroded, but still there.

RwP

 

Simply flushing with water can sometimes suffice but I always suggest adding some Prestone radiator flush and running with it for a day or two. It can be left for an extended period according to the instructions. I ran some through my system before I replaced the radiator. It was one of the first things I did when I got the truck. As a preventive measure, I'd suggest running one thru the system every time you change coolant. Especially you 3.9 owners.

 

Why especially 3.9 owners?

 

Because there seems to be a rash of 3.9L having heater issues.

 

Thanks, just wondered if there was something different about 3.9 cooling systems.