[plantman77]

Solved

[eugene89us]

I would be curious to find that out also. I have changed heater core twice on my 2014 Passat, and they are well known for heater core issues. But F30, you're right - almost nonexistent information. I also understand that most BMWs will requite complete dash removal (unlike VW that is accessible from the footwell). That would make for a tremendous undertaking if that ends up not being the right diagnosis.

[plantman77]

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[davidr3]

If i'm not mistaken its a more common problem in 2013-2014 models

[Phoenix704]

Just curious, but how could it be a bad heater core if one side still blows hot? Older jeeps had problems with the plastic blend doors getting brittle and breaking. The blend doors diverted airflow for dual climate control among the hot and cold sources (heater core vs. evap core). I assume the BMWs would use a similar system to alternate between cold and hot air sources.

If one side blows hot, my initial instinct is that the heater core is at least hot. The climate control system is not appropriately directing airflow for both sides through it.

Pressure test if you want to verify it's not leaking too.

[plantman77]

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[F30lolz]

I have this problem on my f36 with 156k miles. However, after about 20 miles of driving the passenger side heats up but not as hot as the drivers side.

[328iX]

Wouldn't be the heater core if it's able to blow hot, it sounds like a blend door/actuator issue.

[im_an_alien]

Originally Posted by alexp930

I have a 2015 model so it was right before the LCI. I know it does seem like a blend door problem but I figured that would pop a code in ISTA. I can take the glove box out and try to observe the actuators theres like 5 of them.

From what I have been reading the theory is the heater core is clogged on the side that the passenger air flows through. But it doesn't make sense the drive side can melt my hand off.

Also this is after the car sat for a month while I had covid. Suddenly it has this issue. Probably just a coincidence.

There are no coincidences.... maybe you have a rodent issue...

[xavguy]

Check this post. https://f30.bimmerpost.com/forums/sh...ne+side&page=2

I had this issue on my 2014 335 at 44k miles. Heater was blowing hot on drivers side and cold on passenger side. The heater core was replaced under CPO and it's been fine ever since.

[plantman77]

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[Phoenix704]

Reading through that post linked above, it seems like it could be anything from valves to the control unit acting up. Might be worth having an indy shop diagnosing it before you attempt to pull the dash.

Alternatively, since your CPO just expired, maybe your local dealer would goodwill the diagnosis fee if you have had a good relationship with the service center.

Best of luck!

[natesi]

I have a 2016 and would experience the same issues -- HVAC was totally cracked-out, crazy. It would only work decently on "auto" with the AC on.

I read something here, with someone else having the same issue, and they flashed one of the modules that fixed it. So next time I had my car in at the dealership I told them about it and they updated the software in the car -- and now it operates as expected. So, my first suggestion is to make sure the car's software is updated.

[BWbimmer]

I'm not clear on what the heater core is but I had a quick look in TIS and it seems that there are some manuals about heating part replacements. Did you check in TIS?

[thetryal]

so this might sound weird but you could try disconnecting the battery for a few minutes. on my avalanche, this would reset the blend doors. I know the bimmers are different but its worth a shot

[dmaxdmax]

...and I'll just guess/wonder whether it might be a bleeding issue? Not sure how to bleed the f30, but lack of heat issues are often bleeding related.

Maybe an air bubble from a slow leak found its way into the heater core and has blocked off part of the core? Not sure that's likely, but bubbles of air do seem to cause heating issues...easy enough to check out and it's free. (Sounds like a software update might do it for you too.)

[BWbimmer]

Originally Posted by dmaxdmax

...and I'll just guess/wonder whether it might be a bleeding issue? Not sure how to bleed the f30, but lack of heat issues are often bleeding related.

Maybe an air bubble from a slow leak found its way into the heater core and has blocked off part of the core? Not sure that's likely, but bubbles of air do seem to cause heating issues...easy enough to check out and it's free. (Sounds like a software update might do it for you too.)

The best way to even get air pockets out is facuum bleeding

It's acually the BMW recommended way.

[plantman77]

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