so I replaced my thermostat from a low 180 to stock which I think is 195 and at idle the heat pretty much blows cold this time of year. I can rev it up in neutral and it gets better but it's best when moving with force on the motor which the heat is pretty decent.

I let it run with the radiator cap off to get the air out but maybe there's more? Is there a bleeder screw somewhere or am I missing something else? Thanks in advance.

 

Since you do get heat I'm assuming your heater core is not clogged. My guess is your blend doors are stuck open or bad vacuum lines.

 

That could be but they seem to switch over just fine and the a/c works just fine.

 

Did you check your coolant level?

 

Is there a good amount of air blowing at idle or is it blowing cold air at idle?

 

Coolant level is full, I filled it up after I changed the thermo.

It's pretty much blowing cooler air than it is when you rev it up or get moving, especially if your hard on the gas pedal. It's not cold air, just a lot cooler than it really should be and gets worse as it gets colder.

 

Start with flushing the core, 2nd guess would be the water pump is worn and isn't flowing well at idle.

 

I did replace the water pump about a year ago but hmmm the core could be a little clogged.

 

It sounds like a thermostat stuck open When did you replace yours? It is possible to get a bad one, especially with all the chintzy Chinese garbage glutting the parts market these days. 'Name brand' doesn't mean anything anymore; a lot of well-established 'manufacturers' source their stuff from overseas now.

Also, check for a soft, collapsed, or pinched hose somewhere.

Some vehicles are equipped with heater control valves. I don't know what year Dakota you have, or even if Dakotas were ever equipped with such things (I know my '88 doesn't have one), but a faulty, clogged, or disconnected control valve can restrict water to the heater. They're usually vacuum-operated but some are run by a cable and are usually located somewhere under the hood, in the heater core's 'feed' line.

 

It's a 92 and I just replaced it about two weeks ago. I changed it before because it was running hotter to my liking which wasn't bad but I wanted to reduce the chance of blowing a head gasket. Now the temp gage reads a little over the first mark which is hotter than it was on the first change. when it was how I bought it, it read about 45% over the first mark.