My daughter has an 03 tribute (V-6) and it has no heat suddenly. She said her coolant light came on so her boyfriend added coolant to the reservoir but still has no heat. I looked for leaks and didn't find any. The temp gauge stays in the normal range and doesn't over heat.

Can the heater core be bad without leaking like they usually do? What would cause it to have no heat if the coolant level is where it should be?

I thought maybe a hose could be blocked but wouldn't that cause an over heating issue?

 

The thermostat is likely stuck open. The event could have dislodged deposits in the cooling system and ended up in the heater core. You can pinch off the two heater hoses and flush the heater core with a garden hose. I would probably put a thermostat in it and flush the whole system though. (small nozzle end works best for more pressure). It also has a heater door actuator that could be stuck.

 

Is either a new heater door actuator or thermostat an expensive fix? I'm used to the old engines where thermostats took 5 minutes to replace.

 

Labor time on them is less than 1 hour each.

 

I heard that to replace the heater door actuator requires removal of the entire dash, or is that only true for some models and years?

 

It requires some knuckle busting and a small 1/4 inch ratchet with socket, I have never had to remove the dash. It pays .7 hours plus diagnostics. I am sure plenty of shops make huge profits by charging for dash removal. I would replace the thermostat first in any case. It is a maintenance item and not a waste of money by any stretch of the imagination. While the coolant is drained i would flush the heater core so as not to waste time and antifreeze.

 

Well, she got it fixed. First he installed a new thermostat and flushed the system and still had no heat. He said he then "back flushed" the heater core and when he did that, he got heat.

What is "back flushing" the heater core?

 

Coolant goes into the heater core from the engine through one hose and out another hose. Trash will collect in the heater core so flushing it backwards forces the trash out the way it came in.

 

Is a blocked heater core due to lack of maintenance of the cooling system?

 

Possibly, but the antifreeze most manufacturers use today contains sulfates/silicates and break down pretty quickly. This leaves deposits on nooks and crannys in the system. It is best to replace the antifreeze every 2 years no matter what the manufacturers recommend.