1998 Dakota Heat not hot what to check?

[05caddyext]

Been a long time since I had a beater, I don't drive it much even in the summer. It's a 98 Dakota Sport with the 3.6L V6. The heat sucks in it. I checked the anti-freeze level today, it was a little low, so I topped that off. What else should I check? Thermostat bad? In the summer, I recharged the A/C, which wasn't working. It doesn't have an A/C button, you just choose it on the dial. Even when the dial is set to feet/face, not in the A/C mode, the A/C still ran. Is it possible that the switch is bad? When I turn on only the face part, it is luke warm at best. I don't smell antifreeze like I did when I blew my heater core in a mustang, so I guess I am just not sure what to check out.

[88Nightmare]

By 3.6, do you mean 3.9?

Could be switch. Even if the a/c is on and the temp control is set to hot, it should still blow hot. Defroster causes your a/c pump to run to dehumidify the air.

Could have the thermostat stuck open. My 05 duramax suffered from that.

Could have a heater core working on a clog.

Are your temp control doors vacuum or electronic operated? Check for a vacuum leak if they are vacuum operated. Or if electronic, locate the actuators and check their function before replacing anything. My 2005 had a failing temp door solenoid and a failed hvac panel, at the same time. If they are electric actuators, let me know and I can get you voltage specs.

[Ricky Bobby]

Don't know if it's the same design as my 2000 jeep but the doors would break and instead if heat in winter u got frigid air cause they didn't move anymore. Had to have dash ripped out to fix

[Nophix]

Blend door is a common failure point on those.

[Prince Valiant]

If it's just a blend door actuator that's bad, I think you may be able to access it through the glove box. If the door itself has failed, it's a dash removal repair.

[Russ Jerome]

Follow the coolant hoses to the firewall, look for a stupid Chrysler "H" valve that returns coolant to block when heat is off. The valve breaks internaly, can diagnose bye feeling hose temp, if working it should be hot on both sides near firewall. http://i.ebayimg.com/t/NEW-HEATER-BYPASS-COOLANT-CONTROL-VALVE-CATERA-9-5-SAAB-CADILLAC-90-566-947-/00/s/MzM4WDQwMA==/z/DO0AAMXQAMlRXw~o/$T2eC16hHJHwE9n8ikMRbBR(w+n)YJg~~60_12.JPG

[Gregor]

I thought I had a blend door problem. But tried this.

Back flush the heater core? I have a explorer that had the same issue. Deleted the heater coolant valve, it was rusted shut. But this still didn't fix the problem. Took a garden hose hooked it to the output of the heater core and back flushed the system. It took a bit to get enough water pressure to blast out the rust and crap that was in there. And there was a lot. This fixed the heat problem in the Explorer to the point that we almost never have to run it full blast.

The only problem with this is you need to watch the pressure because if it pops the core your done.

[BoosTT]

Feel the hoses going to the heater core.

[spooln30]

If the tstat was stuck open he wouldn't have heat at all.

When the truck is a normal temp check the two heater hoses coming off the heater control valve, like in the pic above. If only one of the hoses is hot then replace the valve. If both seem warm I would check to see if the blend door is actually moving from cold side to hot side. You should be able to hear it, it's like a whoosh of air sound. If ok then I would replace the tstat. Usually what happens over time is the spring and mech gets weak not allowing the valve to fully open and not giving you hot heat. If all else fails just block half of the radiator with cardboard and you'll be good.

[05caddyext]

Is that door something that the dash has to come out to fix? Sounds more like it could be that. Haven't had a chance to run it yet to feel hoses, but when I ran it last here is what I remember. When you set it to floor/defrost that works ok, not hot though. WHen you change to just in your face setting, it's a little warm, however most of the air still comes out of the defrost vents on the top. That would be that door then correct? I really, really, don't want to take the dash out. Had to do a heater core on a fox mustang once and that sucked a$$. I just don't drive it enough to pull it apart. I just don't want the heater core to blow if I don't do anything at all. Thanks for the help so far, I appreciate it.

[spooln30]

If it does have an electronic blend door it should be located behind the glove box. If these are anything like the Jeep Grand Cherokee they are a huge PIA. I did find a easier fix for the blend door where you don't have to remove dash, you just have to cut a hole in the HVAC box and install their kit. The only thing is when the Jeeps door breaks you don't have no heat at all so since yours has some heat I doubt it's the HVAC system. I'd bet it's the t stat or the heater control valve. If you don't want to mess with the t stat just stick a piece of cardboard in front of the radiator