2014 mirage DE heater failure

[scottmarsc]

I have a 2014 mirage DE 5sp MT that suddenly has lost warm air output from the heater. Blower motor works fine, coolant level is OK, engine not overheating- seems to be running at normal temp, lines to heater are both hot, blower motor door actuator works fine, AC seems to work well. I'm at a loss of what else to check, other than consult a dealer (which will be a last ditch desperation move). What have I overlooked or missed?

[Fummins]

Do you have automatic or manual temp controls? Have you checked the cabin filter lately?
Is air coming out the vents as it should, if not take the glove box out and take a look for something that got sucked into the heater box. You'll have to move the selector to recirculate or fresh air(I forget which way) it'll be pretty obvious when you see a big door open up on the top. reduce heat.

Check out about the 40 second mark

[scottmarsc]

Temp controls are set by a digital temperature, so I guess that would be automatic. Cabin filter is OK, and air (cold) comes out of all vents as adjusted by blower motor speed control, which works fine also.

[Christopher_B]

I have a 2014 mirage DE 5sp MT that suddenly has lost warm air output from the heater. Blower motor works fine, coolant level is OK, engine not overheating- seems to be running at normal temp, lines to heater are both hot, blower motor door actuator works fine, AC seems to work well. I'm at a loss of what else to check, other than consult a dealer (which will be a last ditch desperation move). What have I overlooked or missed?

DO you have an infrared tempertaure gun to see if there is a differential in temperature between the two hoses? The return hose should be cooler than the inlet hose as the heater core exchnges the heat from the liquid to the cabin air.

[Top_Fuel]

Go buy a couple of cheap digital thermometers at Harbor Freight. Get your car up to full operating temperature. Turn your heat up to 89 and direct all the air out of your dash vents. Measure the air temperature coming out of the far left (driver) and far right (passenger) vents. Is the passenger side vent a lot cooler than the driver side vent?

Some 2014 and 2015s had issues with internally restricted heater cores. So even with the engine at full operating temperature and hot heater core inlet/outlet temps, you still get reduced heater output.

Go to THIS post and read the PDF file attached. It explains the problem with pictures. This might be your issue.

[inuvik]

Go buy a couple of cheap digital thermometers at Harbor Freight. Get your car up to full operating temperature. Turn your heat up to 89 and direct all the air out of your dash vents. Measure the air temperature coming out of the far left (driver) and far right (passenger) vents. Is the passenger side vent a lot cooler than the driver side vent?

Some 2014 and 2015s had issues with internally restricted heater cores. So even with the engine at full operating temperature and hot heater core inlet/outlet temps, you still get reduced heater output.

Go to THIS post and read the PDF file attached. It explains the problem with pictures. This might be your issue.

That was my first thought also. My 2015 is starting to show signs of blockage. Passenger side is cooler than the driver's. I'll order the heater core without the tubes attached when I replace it.

[Fummins]

I was gonna go to the heater core next but those things usually slowly clog up over time rather than suddenly lose all heat, plus both lines being hot seems odd too. But if the blend doors are working properly and there's no blockage, there's not much else it could be wrong.

[Top_Fuel]

I was gonna go to the heater core next but those things usually slowly clog up over time rather than suddenly lose all heat

I was wondering about that symptom. Sudden (to me) means that it was roasting hot yesterday, but today it's blowing ambient air. I'm assuming this dude turned on the heat for the first time in about 8 months and now it's cold.

My heater (2015) has reduced output on the passenger side. It's manageable and I don't want to touch my heater core if I don't have to. I'll try THIS if I ever decide I need to fix it.

[inuvik]

I was wondering about that symptom. Sudden (to me) means that it was roasting hot yesterday, but today it's blowing ambient air. I'm assuming this dude turned on the heat for the first time in about 8 months and now it's cold.

My heater (2015) has reduced output on the passenger side. It's manageable and I don't want to touch my heater core if I don't have to. I'll try THIS if I ever decide I need to fix it.

Yeah, mine isn't terrible yet, but it's definitely noticeable. After 8+ years I'm still on the OEM coolant so it might be time for some new juice! I've only had to add coolant once since I've owned it. Never gets hot here on the Southern Oregon Coast and rarely (1 or 2 times a winter we might get frost). It's definitely pretty temperate but you gotta be able to take all of the rain.

[Fummins]

I've had good-ish luck with some nasty industrial drain cleaner in old copper heater cores. It helped it long enough until the truck was scrapped.
I almost forgot that these things have that toaster element in the heater box too, so it should be putting out some heat. At least enough to nearly instantly start defoging a windshield in most temps.