I have a dodge dakota 2002 v6 3.9L. I have some problem with my heating, when i'm at a higher speed, like about 50km/h, it all work fine, but when i'm stopped or at a low speed, there's still air coming out but it is cold. I've cheked the engine oil and coolant. What can it be?

 

Low coolant, air pocket in the heater core, failing water pump, clog somewhere in the system, among a selection of other possibilities.

 

I've cheked my coolant and it's fine. What would be the most likely?

 

Too many variables.

If you are just sitting in park, does it do the same thing? Cold at idle, give it a bit of gas, and it gets warm? Any work been done on it lately?

 

Yes it does the same thing on park and if i give a bit of gas it doesn't get warm. No work have been done on it lately. I've cheked a bit online and maybe it could be the thermostat? I'm no expert so i really don't know.

 

If the engine gets up to operating temp, the thermostat is doing its job.

So, sitting still, in park, there is no heat, and if you idle the engine up to 1500 RPM or so, it STILL doesn't get warm??

 

My 98 3.9 was doing the same thing. Disconnected the heater hoses, drained it some, and put some blue devil radiator flush in the heater core only (under half a bottle). After ten to twenty minutes, give it a good, but gentle backflush. Helped mine heat much better. Heater core might be partially clogged, so it's not flowing enough water unless the pump is moving faster.

Edit: You will have to burp it after draining the heater core. Park nose up on a hill, the highest angle you can with the radiator cap off and bring it up to temp temp to try moving any air out of the heater core.