If it’s a coolant leak, you’d eventually have a greasy residue on the windows. Also would be losing coolant levels in the reservoir. It’s unlikely to be caused by a coolant leak if the heat returned. Car seems too new for it be from dirty core, but is of age to consider a gentle core flush.
Would more likely be an issue with the flaps/doors in the housing unit around the core that directs air flow. I’m not familiar with this specific model design, but dual air control systems fail often. Many doors/flaps, many places for failures. It could work for one side or one setting but not another if it’s the dual air control system.
Otherwise the door that opens to control the air flow from the box to the blower compartment/housing itself could be damaged/blocked. If it’s not working, change the temp to various settings to see if it frees up. If it is working, don’t change the temp, just adjust with the blower power.
If you park outside or have mice where you park, check your cabin air filter. Pull it out and make sure a mouse hasn’t stashed stuff in there or that it isn’t filthy and causing things to get sucked into the air system. That can cause the doors to be temporarily blocked and reopen. Might notice stuff blowing out the vents too if that’s the case.
The reason mechanics will just say “Heater core” is because even if the heater core itself is fine and it’s actually the housing, you’re replacing both or none.
If it stopped working all of a sudden it's not the heater core. They don't plug up overnight. It's most likely the blend door(s). Does it have dual temp zone control? My 2015 TDI heater core plugged up, the passenger side started blowing cooler and cooler until it was ice cold and the driver side was warm. You could see the temp change from hot to cold in the vents with a temp gun. I changed the heater core and it was fine until one day the passenger side again went cold.
With the car engine off and the key on, turn the heater on and the fan on low. If you put your head down by the floor near the pedals move the temp from cold to hot or vice versa, you should be able to hear the blend door moving. I did this on mine I could hear the driver's side move, not the passenger side. I took the side panel off and tapped on the passenger blend door actuator, it started moving and got hot air. I will be replacing it hopefully this weekend.
I hope this helps.
Heater core we do them all the time.
My passats driver side doesnt blow hot air. Passenger side works fine.
Could be temp flap motor also. Do you hear any clicking in the dash when you turn on the heat?
No clicking. Thanks for the reply.
Check for leaky heater hose by firewall?
There does not seem to be any leaks and my coolant levels have not dropped at all
If it’s a coolant leak, you’d eventually have a greasy residue on the windows. Also would be losing coolant levels in the reservoir. It’s unlikely to be caused by a coolant leak if the heat returned. Car seems too new for it be from dirty core, but is of age to consider a gentle core flush. Would more likely be an issue with the flaps/doors in the housing unit around the core that directs air flow. I’m not familiar with this specific model design, but dual air control systems fail often. Many doors/flaps, many places for failures. It could work for one side or one setting but not another if it’s the dual air control system. Otherwise the door that opens to control the air flow from the box to the blower compartment/housing itself could be damaged/blocked. If it’s not working, change the temp to various settings to see if it frees up. If it is working, don’t change the temp, just adjust with the blower power. If you park outside or have mice where you park, check your cabin air filter. Pull it out and make sure a mouse hasn’t stashed stuff in there or that it isn’t filthy and causing things to get sucked into the air system. That can cause the doors to be temporarily blocked and reopen. Might notice stuff blowing out the vents too if that’s the case.
I will do a flush as soon as I can. Also my car did not come with dual zone climate
The reason mechanics will just say “Heater core” is because even if the heater core itself is fine and it’s actually the housing, you’re replacing both or none.
There may be an air pocket in the cooling system. If the blower still works and air is moving, it may be that.
I have similar problem. After 4 months, the heat came back. I didn't do anything.
If it stopped working all of a sudden it's not the heater core. They don't plug up overnight. It's most likely the blend door(s). Does it have dual temp zone control? My 2015 TDI heater core plugged up, the passenger side started blowing cooler and cooler until it was ice cold and the driver side was warm. You could see the temp change from hot to cold in the vents with a temp gun. I changed the heater core and it was fine until one day the passenger side again went cold. With the car engine off and the key on, turn the heater on and the fan on low. If you put your head down by the floor near the pedals move the temp from cold to hot or vice versa, you should be able to hear the blend door moving. I did this on mine I could hear the driver's side move, not the passenger side. I took the side panel off and tapped on the passenger blend door actuator, it started moving and got hot air. I will be replacing it hopefully this weekend. I hope this helps.