Heating Issues

[mkeiser]

Hey y'all,

Recently I have noticed my heater not really working in my car. Sometimes the air will feel luke-warm but mostly it is pretty dang chilled. A few months ago I replaced thermostat with a mahle-behr unit and think it's possibly stuck open?

So this evening I fired up INPA and did some digging. I've already bled the cooling system a couple times. The water pump is working properly. The blower fan is properly working. But I'm not sure if the thermostat is working, below are some screenshots of the thermostat live data I took. It seems like I can manually adjust the thermostat opening/closing but whenever it adjusts back to DME value it's back to 0% (I'm assuming this is open). So I'm not sure if the thermostat is working properly but not getting proper signals from the DME? Or if the thermostat is just fucked. Any insight would be much appreciated. I haven't had a chance to check the wiring on the thermostat itself.

Here's an imgur album of some screenshots with descriptions attached. Ambient temps are around 0*F / -18*C.

View post on imgur.com

[spidertri]

The E8x and E9x cars are known to have issues with the heater cores becoming clogged resulting in barely warm air coming out the vents. Lots of people have successfully back flushed them and gotten their heat working correctly.

Check out this thread:

https://www.e90post.com/forums/showthread.php?t=1678039

[mkeiser]

Originally Posted by spidertri

The E8x and E9x cars are known to have issues with the heater cores becoming clogged resulting in barely warm air coming out the vents. Lots of people have successfully back flushed them and gotten their heat working correctly.

Check out this thread:

https://www.e90post.com/forums/showthread.php?t=1678039

I'll have to try that soon. thank you!

[tracer bullet]

Great data. Do you (I don't) know exactly what each measurement is measuring? Is that before & after (upstream & downstream) of the thermostat? Where are those temp sensors located?

Did you notice a change in the heat coming out of the vents throughout the testing?

[mkeiser]

Originally Posted by tracer bullet

Great data. Do you (I don't) know exactly what each measurement is measuring? Is that before & after (upstream & downstream) of the thermostat? Where are those temp sensors located?

Did you notice a change in the heat coming out of the vents throughout the testing?

I don't know exactly where the data is being pulled from. But based on some German wording, "Raw Coolant Temperature" and "Radiator Output Coolant Temperature", I was assuming there is a sensor @ radiator output hose and another sensor somewhere near the engine block coolant passages.

I did a cold start this morning (brrr....) and noticed that the thermostat went to 5% on it's own but then back to 0% real quick. First time i've ever seen it change values on it's own.

It seems like the thermostat isn't doing what it's supposed to do. I still need to check the wiring on it, unfortunately I'm out of town this weekend when it's going to be relatively warm.

View post on imgur.com

[tracer bullet]

Random thoughts - RealOEM might have a diagram or two of the system, pointing out where sensors are located. Also, the thermostat may or not actually open or close, but you are reading the signal going to it asking it to do so (and it is potentially not complying). I don't know for sure but it's possible you read the command and not reality.

Reading the results could also be a little tricky, a t-stat could be only a little open but flowing decently enough to provide heat. Or even if it closed, it could take a while for the temp of what's in the line to cool off, and instantaneous readings can't be expected. It'll probably also end up being dynamic and changing often!

In your first post, the 2nd screen shot for "This is after manually hitting the activation 90% command for a couple minutes" - do you know if you were getting heat in the cabin? Sure looks like the t-stat was open, flowing, and you had hot coolant on both sides. If the cabin wasn't getting warm... starts to sound like a heater core blockage preventing that as the rest of the system looked to be functioning.

Your 4th screen shot "This is after cruising ~60mph on the highway for 15ish mins" - seems odd. It's closed, and it's cold as hell on the output side. I suppose it makes sense factually that the t-stat can be closed and the frigid air running under the hood has chilled the lines way down. But as to why that would happen? That seems like a recipe for a cold cabin. Blocked heater core or not, it seems like there'd be an issue as to why it was closed and was doing that.

I could be way off and misinterpreting.

Historically a t-stat would stick open, the coolant would run in a huge loop non-stop, and never really get a chance for anything to warm up since it was running through the radiator as well which was of course getting ambient air blowing over it. I can't quite tell what is going on here, it's probably not complicated, just new to me. If you do google searches keep it in mind I guess, you may need to go BMW and engine specific.

[1and1]

I suspect I'm oversimplifying this, but here goes-

If the engine temps are behaving normally, I don't suspect the t-stat is a concern. Stuck even partially open/closed (glass half full/empty I guess, eh?) the engine temps would be misbehaving a bit. I'd look that way first for functionality -vs- heater core temps.

Getting cold air from the heater to me is either a blocked(ish) core, or air trapped in the core...

Or vent doors that aren't opening maybe, but that's easy to determine, just a pain to correct lots of air to the passenger, not so much on the driver could well be a door not opening properly.

[mkeiser]

Thanks guys. Driving down south right now so can't respond more in depth. I appreciate all the input, it really helps to bounce ideas around. I think I'll just start with flushing the heater core when the time (temp) is right and go from there. Without knowing more about what inpa is telling me it's tough to accurately pin point any fault on the tstat

Edit; tracer bullet all those screenshots, I had my heat set to 84, AUTO, fan low. No heat throughout the entire drive.

[Marksdreaming]

I'm having similar issues with my heat being cold on passenger side of my 2011 128i. Would this be a partially clogged heater core or is there an other issue with the heater?

[mkeiser]

Originally Posted by Marksdreaming

I'm having similar issues with my heat being cold on passenger side of my 2011 128i. Would this be a partially clogged heater core or is there an other issue with the heater?

From my research that sounds like either clogged heater core or blend doors not working?

There are blend door tests that you can initiate through foxwell scanner and probably inpa.

[Thunderguts]

My heat has never worked properly. It does heat up compared to ambient temperature, but never gets really warm unless I turn it to 84 and then it gets HOT. There's no middle ground.

I previously replaced every hot water hose in the car and the thermostat.

[tracer bullet]

"Blend doors"... I don't knwo what those do. Maybe one of these things I was going to suggest checking:

Whatever is controlled by the HVAC when you set 84F, 75F, and so on.
Whatever is controlled by the dial next to the vent that goes between the hot / cold red / blue squares.

Maybe they are so obvious they were checked long ago. But I could see myself missing it. Wondering why the car is cold and not knowing that the dial by the vent was set to cold. Or contemplating replacing the heater core and not knowing it was an altogether different issue regarding cabin air not going over the heater core and the whole thing was actually an issue occurring inside the car.

[1and1]

If this is what you're asking, then yep, blend doors do exactly that, mix air from different sources to achieve the desired temp & humidity.

Pretty sure I have issues with my pass side blends somewhere since my windshield gets massive condensation with the heat on now, started last winter....

[mkeiser]

i always thought it was weird that our little 1'ers didn't have the typical bmw blue-red center vent dial.

the foxwell scanner is able to actuate the blend doors, so you can at least trigger some things and hear some things happening... hard to really tell if it's working properly or just making funny noises though lol.

oh well... i've got some tubing to flush out the heater core and will probably get to it on Monday, took the day off work and weather is lookin' fiiiiine

[tracer bullet]

Originally Posted by mkeiser

i always thought it was weird that our little 1'ers didn't have the typical bmw blue-red center vent dial.

Hmm, never mind. I was in my X3 when I thought of it. Oops.

[mkeiser]

Heater core flush did the trick! Nice to have some actual heat again I'll post up some pics later

[tracer bullet]

Great news! I'm concerned that it needed a flush to begin with, makes me wonder what happened. But either way it's good it's solved.

[mkeiser]

Originally Posted by tracer bullet

Great news! I'm concerned that it needed a flush to begin with, makes me wonder what happened. But either way it's good it's solved.

Yeah I agree with you there... seems weird to me.

[mkeiser]

Here's some pics... first is the setup I used. 5/8" OD hose fit perfectly in the OEM coolant hoses.

Second is a little sentiment floating when I undid the upper coolant hose.

The rest are the buckets of water flushed through heater core.

[brandon harris]

Originally Posted by mkeiser

Hey y'all,

Recently I have noticed my heater not really working in my car. Sometimes the air will feel luke-warm 192.168.100.1 192.168.1.1 but mostly it is pretty dang chilled. A few months ago I replaced thermostat with a mahle-behr unit and think it's possibly stuck open?

So this evening I fired up INPA and did some digging. I've already bled the cooling system a couple times. The water pump is working properly. The blower fan is properly working. But I'm not sure if the thermostat is working, below are some screenshots of the thermostat live data I took. It seems like I can manually adjust the thermostat opening/closing but whenever it adjusts back to DME value it's back to 0% (I'm assuming this is open). So I'm not sure if the thermostat is working properly but not getting proper signals from the DME? Or if the thermostat is just fucked. Any insight would be much appreciated. I haven't had a chance to check the wiring on the thermostat itself.

Here's an imgur album of some screenshots with descriptions attached. Ambient temps are around 0*F / -18*C.

What coolant do you use ?

[mkeiser]

Originally Posted by brandon harris

What coolant do you use ?

Bmw blue. Pretty sure the PO was using that as well. I don't remember noticing it when I flushed it a few months ago.