[RTguy]

Had my heater core replaced along with the thermostat last year because it wasn't functioning properly. The heat from the vents was coming in as waves of cold and hot.

Fast forward to today, heater core is done again. Vents are blasting cold air and hot air in waves.

I bought a cabin filter and installed it shortly after I replaced the first one as I had assumed the lack of a filter was to blame for my faulty heater core.

What could cause a brand new heater core to go bad within a year??

 

[370 HEMI]

Had my heater core replaced along with the thermostat last year because it wasn't functioning properly. The heat from the vents was coming in as waves of cold and hot.

Fast forward to today, heater core is done again. Vents are blasting cold air and hot air in waves.

I bought a cabin filter and installed it shortly after I replaced the first one as I had assumed the lack of a filter was to blame for my faulty heater core.

What could cause a brand new heater core to go bad within a year??

Double check the thermostat and make sure that the coolant level is correct. Make sure you aren't loosing coolant while the degas bottle isn't introducing coolant back into the engine. Engine could be low and the bottle is still full!

Also typically if everything else is good than an improper coolant will accomplish what you are experiencing again!

When we mention that we don't have the "gunk" in QuantumBlue HP Gold Coolant, what we mean is that there isn't any sodium silicates, sodium benzoate and no sodium tetraborate along with a lack of sulfates that turn to silicon dioxide!

This is what ends up in the radiators, heater cores and the blocks of the engines. HOAT means Hybrid Organic Additive technology. Read organic as Inorganic and organic Sodium!

This is why we convert so many people here over to our QuantumBlue HP Gold Coolant so that you avoid these crappy situations.

Regards,
Brian
BND Automotive LLC:driving:
440-821-9040
www.bndautomotive.com

 

[Hambone]

I had similar issues. There's a thread about it somewhere around here.

http://lapointauto.com/cgi-bin/search.cgi

It's likely an electronic issue, not a core issue. Your dealer sounds like an even bigger richardhead than mine was.

I had that erratic hot/cold issue on my '13 Charger. The shop fiddled with it numerous times, the first thing they did was replace the blend door.
THEN they decided it was an electronic controls issue.
They finally replaced the radio because that is connected electronically to the HVAC.

None of these actions fixed the problem.

Oh, that was after they got the wrong radio in and I wasted a trip out there to drop the car off.

Finally they ordered a main cable and were going backwards up the chain to lord knows where.

This was over the course of about eight visits to the service department. With no end in sight.

I finally ran out of time and patience.

I simply was not interested in spending time shuttling the car back and forth to the dealer or waiting around for an hour or two while they played with it.

So I traded it. Good luck.

 

[msv2015]

Do the waves of hot and cold coincide with accelerating and not accelerating, respectively? If so, I'd have the water pump impeller checked. Other possiblity is the intake port on the heater core is restricted and if you answered yes to the question above, that could be it, especially since your on the second heater core. Why change the thermostat by the way? You have to repair things one item at a time. The heater core may be restricting because of contaminants circulating through the system - which were could have already been there early on. Put back an OEM thermostat, replace as much coolant as you can get out, then blow out the trash in the heater core in the reverse direction of coolant flow. That might just do it. The heater core is usually not something that just fails on its own, it's a symptom of another problem.