[DakotaFan99]

Hey guys,

I have a 99 Dakota 3.9L V6 and I'm having an issue with luke warm heat coming from the vents after the truck is fully warmed up.

My thought is maybe the blend door actuator is messed up, but I'm not sure. The heater hoses going into the heater core sem pretty hot ~160 F on the top hose, ~110 on the bottom hose. Does this sound right/normal?

Is there a blend door actuator on this truck? I see references online to the blend door being electronically controlled, vacuum controlled, or cable controlled.

Any help would be appreciated

 

[OFWG]

Back flush your heater core. Remove both hoses on the heater core at the fire wall. Using a water hose with a sprayer force water into one core tube and then the other. Keep rotating between the tubes until the water runs clear. Reconnect the hoses and enjoy your new found heat.

 

[DakotaFan99]

Thanks for the reply. I'll give this a shot this weekend.

 

[adnedarn]

How are you determining that the truck is fully warmed up? Your thermostat should be 195f (unless you've opted for the 180f for some reason) so it seems to me the heater line should be warmer. Maybe your thermostat is stuck open.

 

[AandPDan]

There is no blend door actuator, it's cable operated on your '99.

Sounds like a partially clogged heater core. Agree on the back flushing.

 

[Rahool982]

Another vote for backflush. Had same problem with mine a few years ago and the backflush did wonders

 

[daddyododge]

How are you determining that the truck is fully warmed up? Your thermostat should be 195f (unless you've opted for the 180f for some reason) so it seems to me the heater line should be warmer. Maybe your thermostat is stuck open.

I agree with back flushing also.. Also I agree with the thermostat from the factory was 195f. The water
flowing through heater hose from engine should about 185 to 195.
Change the thermostat also.
Daddyododge

 

[FESTER]

I did the back flush thing and it helped, But the real issue was the truck just wasn't getting hot enough. I blocked off a large portion of the radiator with a piece of water proof art type board from Dollar Tree. Got the temp up near that 210 degree mark. Huge improvement. You may need to adjust the width to get it right. Just leave enough sticking out the top to make it easily removable.

 

[daddyododge]

If your truck has a automatic transmission, blocking off part of the radiator is a bad idea.
The transmission cooler is also part of the radiator. This may cause the transmission to also
heat up and cause damage. The thermostat and new antifreeze is a lot cheaper
then a new transmission!!!!

 

[FESTER]

I am only blocking off part of the core, not any of the lower tank.

 

[Patrick012]

Back flush your heater core. Remove both hoses on assurance chien the heater core at the fire wall. Using a water hose with a sprayer force water into one core tube and then the other. Keep rotating between the tubes until the water runs clear. Reconnect the hoses and enjoy your new found heat.

This is really interesting information for me.