I'm having the infamous heater core issue where when the AC is on the heater core produces an insane amount of heat to the point where it gets extremely uncomfortable to drive with. Anyways I'm in the process of insulating the area to help with the heat and noticed that the heater core had a couple drops around the fitting along with some corrosion on the fitting itself. I attached an image below. Is this an issue of concern, and could this be part of the reason why its getting so darn hot?

 

I am not familiar with this problem. From what I can discern from your post, you are driving with the A/C on (temperature set at cold?) and hot air is coming from the vents? Or temperature radiating from the heater core near your feet is making your feet hot?

The heater core should make the same amount of heat at all times (once the engine is at operating temperature) since it is part of the engine cooling circuit. I've never measured the temperature directly at the heater core, nor the pipes to/from it but engine coolant normally is around what, 200 degrees F? I have measured heat coming from the vents with the heater on full hot (A/C compressor on) and normally see temperatures around 170 degrees +/- 10 degrees or so.

Not sure if this helpful.

 

That's how it's supposed to work, but it just doesn't seem to be that way for some of us. I bought the car in the winter and never used the AC (cold) until recently. The heat is so bad that I'm planning on selling the car within the next couple weeks.

Heres another short thread about it:
https://www.northamericanmotoring.co...r-on-feet.html

 

Interesting. Thanks for the link.

When I'm with my car again, I'll look in the drivers side footwell to see if there is some insulation shielding the heater core pipes from my foot because my car does not roast my feet. A quick look on RealOEM.com, I found this part. Does your car not have that shield or does the heat radiate through that?

 

No it is just a cover. Some folk do not put it back on if they have been working on the heater core. The screw in the back is a bastard to remove an reinstall.
You may want to check that heater core to make sure it is not blocked. As the other poster stated. The core is always at the same temp once the engine come to operating temp. Your dampeners determine the temp based on what you set it at by mixing cold air to heat.

 

Yes the plastic is on there, and yes that screw was a ***** to remove (took me an hour just to find it). I did some more diagnosing and I found out a couple more things. The hot air is actually blowing onto my feet from under the plastic cover, as if a fan is doing it (no its not my ac vent either). Also even if the plastic cover isn't installed correctly, the plastic itself still gets too got to touch for more than a couple seconds so I don't think that's it either. I can do more troubleshooting if you guys have more ideas

 

Now I'm really intrigued.

I'm in the middle of an engine replacement on my R53 but once I get it running, I want to see how the heat is down there. In my 19 years of ownership, 16 of those years in Arizona with frequent A/C usage, I have never experienced heat in the footwell like Panzu describes. Perhaps it's because the ambient air temperature is so high, the heat from the heater core just blends in!

 

I think I may be onto something, I'd like an outside perspective. This morning was cold so I turned the heat on (as opposed to the AC) however after the car warmed up I decided to turn off the blower for my feet and yet again, hot air was still blowing from around the heater core. This confirms something I read about online. "There is a plastic flapper door and an actuator that controls whether you get hot or cold air" I'm thinking that the 'flapper door' is stuck open and therefore forcing heat through whenever the fans are on. What are your thoughts on this? What do you think my next steps should be? I'm going to try and poke around RealOEM.com as you linked earlier, but I'm not sure how much success I'll have. Thank you for any help!


Helpful thread(s) in my research:
https://www.bimmerfest.com/threads/h...-open.1267434/
https://www.northamericanmotoring.co...-constant.html

 

Well I took out my glovebox to watch and see if the blend door was working properly, and it looks like it is. I'm not sure if I'm checking the right one but to me this looks to be it. I circled in red actuator and in blue the actuator door. To me it looks like it opens and closes just fine. Any further suggestions?

 

You are looking at the mix door. Wrong door

see my thread “heater not working”. Everything is there

 

@Panzu
For your consideration here is the link to ssoliman's thread: No heat / heater not working
I'm having a similar issue, with cabin air ducts. Looking for clues as well.
Hope you can get your issues worked out.

 

Thanks for the link. Unfortunately his issue isn't actually the same as I'm having. The issue is that heat is coming from the heater core itself, and not from the vents. There is hot air blowing from under the cover that's over the heater core. So whenever a the fans are on, no matter what temperature it's set to the heater core blows hot air out. Not from the vents, but the air comes from around the heater core itself

 

If air is blowing out anywhere other than the vents, it sounds like a problem with the ducting. Have you checked that all ducts are properly connected?

 

I have not, but I'll look into it thanks for the suggestion. My guess is that the air is coming from the fan on the heat core. I'll try to check the ducting around there tonight