Plugged heater core. BMW F32 435i

BMWTurboDzl

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My vehicle developed a no heat condition and I think I've narrowed it down to a plugged heater core. There's a heater control valve on the inlet hose which controls the amount of heated coolant making its way to the heater core. My diagnosis is based upon the fact that the inlet hose between the control valve and the heater core is warm which leads me to believe that the control valve is functioning. The outlet hose is cold.

I'm wondering what sort of experience people have flushing the core only OR whether you guys think it's easier to just use a cleaner flush on the entire system?

Recommended products? Liqui Moly, Motul, and others have a 500 ml "pour-n-idle" product.

My engine (N55) has an electric water pump and I don't have a block drain so I don't know how I would flush out any cleaner.

UPDATE: 63k miles on the odo. 2015 MY
 
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BMWTurboDzl

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How do you know the valve to the heater core is open? How do you know the door that directs air over the heater core is properly actuated? And finally, is there enough coolant in the system. A small amount of missing coolant will leave an air bubble that can, on some cars end up in the heater core. It will act as very poor heat levels. It happened on my Pontiac Vibe last month. No one on this site believed me but adding 4 ounces of coolant and burping the system fixed the issue. I doubt you have a clogged heater core.....remember the heater core itself does not hold much fluid so a 4 ounces of air is significant.
As I said in my OP the hose between the valve and the core is warm. The output hose was ice cold.

I spoke with another technician and he said that input hose should be hot not warm. So I should compare the temp of each section before/after the HCV. Hot hose before / warm hose after = probable failing HCV. If both hoses warm could be aux heater water pump if I have one i don't think I do.

The hoses and HCV are easily accessible due to the I6 layout. See post #27 showing the part.

Coolant level is fine.

I could also be the blend door or broken wire or SW issue but I really have no idea w/out a code reader.
 
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As I said in my OP the hose between the valve and the core is warm. The output hose was ice cold.

I spoke with another technician and he said that input hose should be hot not warm. So I should compare the temp of each section before/after the HCV. Hot hose before / warm hose after = probable failing HCV. If both hoses warm could be aux heater water pump if I have one i don't think I do.

The hoses and HCV are easily accessible due to the I6 layout. See post #27 showing the part.

Coolant level is fine.

I could also be the blend door or broken wire or SW issue but I really have no idea w/out a code reader.
Hot input and cold output would indicate you have flow and the heater core is taking the heat. No flow and the input line should maybe be only luke warm.
 

OVERKILL

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As I said in my OP the hose between the valve and the core is warm. The output hose was ice cold.

I spoke with another technician and he said that input hose should be hot not warm. So I should compare the temp of each section before/after the HCV. Hot hose before / warm hose after = probable failing HCV. If both hoses warm could be aux heater water pump if I have one i don't think I do.

The hoses and HCV are easily accessible due to the I6 layout. See post #27 showing the part.

Coolant level is fine.

I could also be the blend door or broken wire or SW issue but I really have no idea w/out a code reader.
The technician is correct, the hose going into the core should be HOT, the same temp basically as your other hoses, if it is only warm, there's no flow going on there and the heat is just coming from convection. There will be some loss through the core (the exit hose will be warm vs the hot of the inlet hose) but it sounds to me like it's the valve, as he and you are now both suspecting.
 
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Quick Q. Assuming you have protool, are codes in english or german? I watched a video which suggested german but I wasn't sure if that was due to a user setting.
I actually don’t. But will install soon as I need to tune DME for 3 stage intake.
Did you check Bimmergeeks web site? I think they have all correct versions of INPA and ISTA.
 
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How do you know the valve to the heater core is open? How do you know the door that directs air over the heater core is properly actuated? And finally, is there enough coolant in the system. A small amount of missing coolant will leave an air bubble that can, on some cars end up in the heater core. It will act as very poor heat levels. It happened on my Pontiac Vibe last month. No one on this site believed me but adding 4 ounces of coolant and burping the system fixed the issue. I doubt you have a clogged heater core.....remember the heater core itself does not hold much fluid so a 4 ounces of air is significant.
The heater core AND the AC evap both get all airflow. The heater core is under the AC evap. Why? The evap has a temperature sensor which is used to detect when the evap is nearing the freezing point. At that point the automatic climate control module (IHKA in BMWspeak) opens the heater control valve enough to warm the air going up and through the evap, thus preventing evap freeze up.

OP, I'm betting the heater control valve is the culprit. The valve is open unless the IHKA supplies electrical power (constant or pulsating 12VDC, depending on the the cabin and exterior temperatures). What's happening, IMHO, is the valve is partially blocked. I recommend that you have the coolant replaced once this issue is resolved. I do not buy into BMW's 5 year coolant protocol. I had my coolant changed at 4 years and 22k miles. ALWAYS use BMW coolant and DISTILLED water!
 
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