[Walletsr]

I have a 07 e90 335. A couple weeks ago before it began to maintain subzero temperature here on Minneapolis I changed out my coolant. I had heat and equal air flow coming out of all my vents.

After I changed out my coolant winter came and I started using my heater. I noticed that my heat was cooler than usual so I drained my coolant and back flushed my heater core. That didn't fix the issue and then I had a passenger and they mentioned they had no air on their side as well as it was cold.

I then stuck a flexible rod up the vents to try and see if there was anything stuck, which there wasn't.

When I leave the air source as fresh air minimal air flow will come out passenger side and that air is significantly colder than driver side. The heat will work on all vents when I put the heat on recirculation, but the issue is that all my windows get fogged up due to the moisture.

I peered into all the vents with a light and didn't see any oozing or gunk from a heater core leak. I also have looked under driverside and didn't see any leaking from the heater core area.

My heater core hoses are equally hot for intake and output, so I don't believe it's a bad heater core.

I have ordered a new fan, master relay and heater core just in case

Cliff notes:
Flushed coolant and back flushed heater core
Minimal air flow and heat on passenger side.
No known issues prior to coolant flush

Any help would be greatly appreciated

[BKV122]

Kind of similar scenario happening to my mothers 3 series, except no heat what so ever and perfect airflow. I believe she had her coolant changed in the fall and drove up from Florida for the holidays with no heat

[F30Mo16]

I never had heat in my car. Being in florida it is rarely used, however sometimes it would be nice. My heat jus doesn't work. And now when the AC is on, sometimes it looks like steam is coming on. Even on hot days and i just used it and turned it off, it continues to steam out of the vents even if the car is off. Not sure what my deal is.

[bmwhitman]

Originally Posted by Walletsr

I have a 07 e90 335. A couple weeks ago before it began to maintain subzero temperature here on Minneapolis I changed out my coolant. I had heat and equal air flow coming out of all my vents.

After I changed out my coolant winter came and I started using my heater. I noticed that my heat was cooler than usual so I drained my coolant and back flushed my heater core. That didn't fix the issue and then I had a passenger and they mentioned they had no air on their side as well as it was cold.

I then stuck a flexible rod up the vents to try and see if there was anything stuck, which there wasn't.

When I leave the air source as fresh air minimal air flow will come out passenger side and that air is significantly colder than driver side. The heat will work on all vents when I put the heat on recirculation, but the issue is that all my windows get fogged up due to the moisture.

I peered into all the vents with a light and didn't see any oozing or gunk from a heater core leak. I also have looked under driverside and didn't see any leaking from the heater core area.

My heater core hoses are equally hot for intake and output, so I don't believe it's a bad heater core.

I have ordered a new fan, master relay and heater core just in case

Cliff notes:
Flushed coolant and back flushed heater core
Minimal air flow and heat on passenger side.
No known issues prior to coolant flush

Any help would be greatly appreciated

Did you bleed the cooling system ?

[robthewrench]

You're probably not going to want to hear this, but based on other posts from other owners, your heater core is partially clogged.

Prior post example:

http://www.e90post.com/forums/showthread.php?t=504111

[TGTIW]

Your symptoms do sound consistent with it being the heater core.

When I had the dealership do mine, I can tell you that the core can be replaced without removing the dash. It's not the ideal method, and it involves some bending, but I think I preferred this approach rather than having that group of incompetent idiots dismantle my dash.

[Walletsr]

Please tell me more about changing core without pulling dash. I will do it myself when it's above 30. Right now I get no more heat when just the heater is on but if I turn on recirculation I get heat normally.

How does it get heat instantly on recirculation but no heat otherwise?

I have flushed and bled it twice this past weekend still no change.

[TGTIW]

I can't emphasize enough that it's not the ideal method. The heater core itself slides out of the housing in the direction of the drivers footwell. There is a dash support bracket that is in the way. From what I can tell by examining the work after it was completed, my dealership bent that bracket out of the way and slightly bent the inlet and exit pipes on the core. Once the core was slid into place, they bent the bracket and hoses back into position.

[Walletsr]

I see how they can do it now. Worst case you break a hose and replace it anyways still cheaper than the 2.5k-4k quotes I have received

[Walletsr]

Wasn't able to change out heater core as it was - 10 all weekend, but I do notice when I stop moving my vent Temps get significantly warmer.