[f30fan123]

I have a 2014 BMW 335xi that is producing NO HEAT in the cabin at all. I've searched the forums for solutions to this issue and the only answer I found was to replace the thermostat. So I did. Unfortunately I still have no heat inside of the car. Even after bleeding the system multiple times.

Another issue I am having that might be related to my heat issue is the amount of air being pushed through the vents. When I have the fans turned all the way up I can hear the blower motor pushing air through but it feels like there is not a lot of air coming through the actual vents. I have checked the blower motor and there is no debris in the housing. The motor seems to be working just fine.

The only ideas I have at this moment are that the heater blend actuator is not working properly and that is causing low air pressure and as a result, no heat to the inside. Another possibility is that my heater core is clogged but strangely enough, if I leave my fans turned off and the car is up to temperature, I can turn the fans on low and for a few seconds I can feel heat through the vents.

Has anyone else had this issue before on their F30??? I am looking for any ideas/help I can get at this point being that its getting nice and cold up here in Ohio and I now have to wear a winter hat, gloves, and jacket just so I don't freeze on the way to work.

[zeikei]

Get your fault codes read with ISTA or some other BMW specific tool, most of the issues with flaps or motors will leave a code. Did it gradually get like this or all the sudden? Any difference if you turn on the windshield defrost mode? I am afraid it is clogged heater but let's hope it is something easier.

[njdangelo]

not trying to be 'that guy' but you do have the dial in the upper middle of your dash set on the red right?
If you switch the air location (feet/dash/windshield) does the air come out of the requested vents? if so i would think your blower is working properly.

[dmaxdmax]

...and if you haven't changed your cabin air filter in years, that can clog so there's not much air to push anywhere.

...and I'm not sure how you bled the system, but I know that bleeding is often the solution to no heat too. How did you bleed? Have you revved the car to knock air bubbles out?

[njdangelo]

I'm going to assume by the lack of response that it was the center temp button...

[f30fan123]

Originally Posted by zeikei

Get your fault codes read with ISTA or some other BMW specific tool, most of the issues with flaps or motors will leave a code. Did it gradually get like this or all the sudden? Any difference if you turn on the windshield defrost mode? I am afraid it is clogged heater but let's hope it is something easier.

It has gradually gotten worse and the defrost is no better than the normal vent heating. Most likely my heater core.

The fact that the air pressure through the vents only on the hotter temperatures is worse than if it was set to a low temperature is the only confusing part.

[f30fan123]

Originally Posted by njdangelo

I'm going to assume by the lack of response that it was the center temp button...

The center temp dial doesn't do anything unless you have the A/C button on and no that is not the issue.

Cabin air filter was changed. I just checked for codes using BM3 but it said there are none. I am aware this way of checking codes is not the best but its what I had available at the time.

**UPDATE** After driving home (40 minute drive) I went under the hood and felt the feed and return lines leading to the heater core flanges on the firewall. The feed line was hot and had decent pressure while the return was cool to the touch and didn't seem to have as much pressure in it. With that being said, I think its fair to assume that my heater core is probably clogged. RIP to me. I will try flushing it out this weekend. Wish me luck. I will update again if my issue persists after the flush.

[zeikei]

Originally Posted by f30fan123

The fact that the air pressure through the vents only on the hotter temperatures is worse than if it was set to a low temperature is the only confusing part.

Maybe the system does not open the flaps fully because it senses that the air from heater is so cold compared to the requested temp that it would just make things worse.

[njdangelo]

Originally Posted by f30fan123

The center temp dial doesn't do anything unless you have the A/C button on and no that is not the issue.

Cabin air filter was changed. I just checked for codes using BM3 but it said there are none. I am aware this way of checking codes is not the best but its what I had available at the time.

**UPDATE** After driving home (40 minute drive) I went under the hood and felt the feed and return lines leading to the heater core flanges on the firewall. The feed line was hot and had decent pressure while the return was cool to the touch and didn't seem to have as much pressure in it. With that being said, I think its fair to assume that my heater core is probably clogged. RIP to me. I will try flushing it out this weekend. Wish me luck. I will update again if my issue persists after the flush.

"The center temp dial doesn't do anything unless you have the A/C button on and no that is not the issue. "

Interesting. Mine works whether A/C is on or off

[BWbimmer]

There is a shutoff valve in the heating circuit 64119254742. This might be blocking the flow. You describe the return pipe being cold. Maybe this is the reason.

I think you really need a code scanner otherwise you might lose a lot of time finding the issue.

[psyki]

Originally Posted by njdangelo

"The center temp dial doesn't do anything unless you have the A/C button on and no that is not the issue. "

Interesting. Mine works whether A/C is on or off

This is correct, the dial simply mixes in cooler air whether the A/C is on or not. I leave the climate control at 70 year round and only adjust the dial depending on whether I want it warmer or cooler in the car.

[f30fan123]

Originally Posted by BWbimmer

There is a shutoff valve in the heating circuit 64119254742. This might be blocking the flow. You describe the return pipe being cold. Maybe this is the reason.

I think you really need a code scanner otherwise you might lose a lot of time finding the issue.

I checked the pressure before and after the shutoff valve and it felt the same but I am not entirely sure how the shut off valve works in conjunction with the heater core. I will try to flush this weekend and if the problem still persists, I guess I will just be out of luck.

[BWbimmer]

Originally Posted by f30fan123

I checked the pressure before and after the shutoff valve and it felt the same but I am not entirely sure how the shut off valve works in conjunction with the heater core. I will try to flush this weekend and if the problem still persists, I guess I will just be out of luck.

Btw, the valve only exists on cars with M-Sports package, which I only guessed you've got
If not then there is not much going on:

https://www.realoem.com/bmw/enUS/sho...diagId=64_1901


It's an enclosed system so it's clear that the pressure is the same on both sides.
Important would be to know if the temperature before and after the valve is the same. If not then the valve doesn't open. This could be a mechincal or an electrical problem.

I don't think is doesn't make sense to flush the system over and over again. Btw, Did you refill with a vacuum pump or just the old style?