Heater Core or Blend door acuator?

[deeman]

So a guy needs help diagnosing an issue on a 2008 RWD 3.0l
3 weeks ago when I started it and turned on the AC I had a blast of steam come thru the vents. I stopped and there was a really big amount of vapor coming from under the hood right near the heat exchanger.
I did smell coolant and continue to smell coolant when turning on the heater however the windshield fogs up bad (coolant vapor film?) and my defrost seems to blow heat but the windshield never unfogs
So…..heater core is bad, right?
But the heat works perfectly and my engine temp is not abnormal at all.
I have no moisture or dampness on the passenger footwell
I thought a heatercore issue would not produce heat and my engine temps would be abnormal.
Could it be the blend acuator?
Any way to rule in or out a bad heatercore?
Thanks

 

[rusty ol ranger]

So a guy needs help diagnosing an issue on a 2008 RWD 3.0l
3 weeks ago when I started it and turned on the AC I had a blast of steam come thru the vents. I stopped and there was a really big amount of vapor coming from under the hood right near the heat exchanger.
I did smell coolant and continue to smell coolant when turning on the heater however the windshield fogs up bad (coolant vapor film?) and my defrost seems to blow heat but the windshield never unfogs
So…..heater core is bad, right?
But the heat works perfectly and my engine temp is not abnormal at all.
I have no moisture or dampness on the passenger footwell
I thought a heatercore issue would not produce heat and my engine temps would be abnormal.
Could it be the diverter?
Any way to rule in or out a bad heatercore?
Thanks

Nah...a plugged core wont make heat...but a leaky one will...and make everything foggy and stink like coolant.

Strange your floors not wet. But im still betting the core is shot

 

[rubydist]

Typical symptom of a heater core with a smallish leak.

The blend door actuator has no ability to make those kinds of issues.

 

[deeman]

Okay, thanks guys - I also suspect the HC needs to be replaced but I wanted to check to be sure.

 

[rubydist]

If the heater core has a small leak towards the top, the heat from the circulating hot coolant can evaporate all of the leaking coolant before it can make a wet floor. That is likely why the windshield is so fogged up. Alternatively, it could be running into the engine bay on one of the inlet/outlet ports so it never drips inside the cab.