[335i101]

I guess the mobile version can't "double quote" anyway I answered your question in my previous post (it just doesnt look like it as it didn't shade your original post)

[F30Mo16]

Originally Posted by 335i101

They disconnect the coolant lines running into the heater core and blast air into it in hopes of unclogging it.

The heater core itself is about 150.00 its the labor that adds up....the whole dash get removed.

I have been searching for a DIY to remove the dash but I can't seem to find one.....the heat on my side of the car is good but the passengers side is cold.

U r in FL, stop yur complaining... I am WI!!!

LOL I'm not complaining at all I even said I'll be okay riding around with a blanket lol! I know FL has no real cold!

I just close the passanger vents and tell my passangers your shit out of luck... lol

[zigsman]

I seem to be having the same issue. 2006 330i (E90). The driver side vent blows scorching hot heat but the passenger side is only luke warm. The water pump and thermostat were replaced a few months back. I removed the glove box and visually observed the stepper motor cycle as I changed the temp for the passenger side and could feel a noticeable temperature difference but I still only get warm air when I set the temp to 84. So, I know the motor is good. I find it hard to believe that it is the heater core as I get such hot air on the driver side. The E90 only has one core ( I guess some older models have two), which means the heat for both sides of the car come from the same core. How is it that I get hot air on one side and only warm on the other...all from the same core? I am inclined to believe that it may be a faulty flap/blend door?? Thoughts?

[335i101]

Originally Posted by zigsman

I seem to be having the same issue. 2006 330i (E90). The driver side vent blows scorching hot heat but the passenger side is only luke warm. The water pump and thermostat were replaced a few months back. I removed the glove box and visually observed the stepper motor cycle as I changed the temp for the passenger side and could feel a noticeable temperature difference but I still only get warm air when I set the temp to 84. So, I know the motor is good. I find it hard to believe that it is the heater core as I get such hot air on the driver side. The E90 only has one core ( I guess some older models have two), which means the heat for both sides of the car come from the same core. How is it that I get hot air on one side and only warm on the other...all from the same core? I am inclined to believe that it may be a faulty flap/blend door?? Thoughts?

It is just one core, but it's clogged. It gets crazy hot on one side correct??

The coolant comes in and, in my case, could return back out of the heater core as both hoses were warm.

The service guy said that the cores gets a build up of some sort of deposit and it is not an uncommon problem.

(pretty strange to be happening on an 07 IMHO)

I brought it to Indy, dealership and worked on it myself...everyone concludes heater core.....good luck!

[335i101]

Originally Posted by zigsman

I seem to be having the same issue. 2006 330i (E90). The driver side vent blows scorching hot heat but the passenger side is only luke warm. The water pump and thermostat were replaced a few months back. I removed the glove box and visually observed the stepper motor cycle as I changed the temp for the passenger side and could feel a noticeable temperature difference but I still only get warm air when I set the temp to 84. So, I know the motor is good. I find it hard to believe that it is the heater core as I get such hot air on the driver side. The E90 only has one core ( I guess some older models have two), which means the heat for both sides of the car come from the same core. How is it that I get hot air on one side and only warm on the other...all from the same core? I am inclined to believe that it may be a faulty flap/blend door?? Thoughts?

Also it will get worse....when I first bought the car it was tolerable on the passenger side, then it became ice-cold and then the drivers side started getting cold....

That is when I took it to the dealer (had previously had Indy work on it for 6 hrs and worked on it myself)

Dealer said all electronics and "flappers" were all good....

[zigsman]

I hate to hear that...i was/am really hoping it is not the core, not that I doubt what I read on the board, as that seems to be the most common solution. Beings I have troubleshot all the electronics, I'm not sure what else it would be anyway. I am still confused as to how it could be the core though, maybe my understanding of how it works is distorted. It the core is like the radiator, one way in and one way out, I would imagine either you have a partial blockage and the entire core still gets hot or warm (evenly) or it is completely blocked and provides no heat at all.

[zigsman]

Originally Posted by 335i101

Also it will get worse....when I first bought the car it was tolerable on the passenger side, then it became ice-cold and then the drivers side started getting cold....

That is when I took it to the dealer (had previously had Indy work on it for 6 hrs and worked on it myself)

Dealer said all electronics and "flappers" were all good....

Assuming it is the core, my question is this, Is this a repair I can do at home? I am a well qualified mechanic (with vehicles and aircraft) just not certified. I have always worked on, modified, and repaired all of my vehicles and I have the entire TIS for the E90. I am fully cable of this repair, however, the software/programming issue concerns me. I have limited software for the car "BavarianTechnic" which is great for diagnosing and troubleshooting the vehicle but I worry that I may need a full "reprogram" after removing and reinstalling the stereo, instrument cluster, airbags, steering column...etc. If after I complete this, am I going to be stuck with a very large, very expensive paper weight that I will need to have towed to a dealer to have it reprogrammed?

[335i101]

Zigsman,

Like you, I was first in disbelief that it was the heater core, I figured it would all go bad or non of it go bad. I also had non of the "normal" signs of the core. Coolant smell, misty windows, damp carpet etc....

And I have learned more since my original post, since bringing it to the dealer and pleading with them that it was anything but the heater core:

*there is no water valve that "normally" is the culprit on this version of the 3 series

*After BMW said it was the heater core, last week or so I didnt believe them (see my old DME Warning post were the dealer almost "F" me out of 2k, I don't believe it was intentional) so I started calling local Indys...I told them the "tests" the other indy shop and BMW ha run and they agreed it was the core

*BMW said that a backflush of the core had never solved the problem and that it would cost 200-some dollars...the Indy shops, work on Bimmers are not experts IMO, and they all said a flush would fix it.

*I called the dealership back and said to do the flush as I already owed them 60.00 for there time, they said because of either the fluid or material inside the core (I don't remember) that it was extremely unlikely a flush would solve it as calcium deposits "grow" in the core and cause partial clogs that can't be flushed.

*I was sick of being cold and know the cost for heater core was 2k, as thought, "what the hell.". After the flush the dealership felt bad for me that it didn't work and charged me 150.00.

*I noticed a slight improvement when I turned the knurl knob, as in the past it did little to nothing, other than that, passenger side still cold, my feet still on fire and my vents/deferost are luke warm.

OK NOW ON TO THE REPAIR:

*There are 2 brands/models of cores that were used denso and valeo. They are both around 100.00 but was told that u don't know which one u have until u remove it. (I think that is wrong as I pretty sure I recall therealoem showing the 2 cores based on production year/month.

*I am patiently waiting for a DIY as I have been getting more PM on this problem from other members since starting it last year...also every member I have talked to resolved the problem by replacing the core...some did thermostat/water pump only to end up having to replace the core in the end.

*After talking to the SA (not the mehicanic) their was no mention of reprogramming. I would think if u fully disconnected radio, there may be something to "code" but not mention was ever made of that...they just said, "The parts are cheap, it is an expensive fix since the entire dash has to come out."

THAT IS ALL I KNOW, I AM WAITING FOR SOMEONE WITH A BIGGER "SET" THAN ME TO TRY IT FIRST AND POST A DIY.

IMHO, I am sure if u r a skilled mehicanic u can do it...the one concerned u alread mentioned is the "paperweight" possibility...not sure how close u live to a dealer but after doing the install if a tow to the dealer and 100.00 "coding" bill is the only extra cost I, personally would take that chance (and save 1700.00 or so in labor).....I am more concerned about getting to the core.

Keep posted as I would be more than happy to attempt this project together (virtually) on some weekend with pics/videos to each other and working through it.

GOOD LUCK

A side note, when I had the care in the dealer pointed out a small oil leak at the oil filter base....wanted 610.00 to fix it (others on this forum were quoted 800.00). Dealer said 4-5 hours of labor and 20 dollars in parts....I bought the gasket and fixed it in 2 hours or so....point being I don't think it is as difficult as the price implies.

Ok that was a long message to type on my phone..my hands are cramping



GOOD LUCK!! (I am not gonna double check this whole message for spelling and grammar so please forgive any mistakes..)

[zigsman]

Originally Posted by 335i101

Zigsman,

Like you, I was first in disbelief that it was the heater core, I figured it would all go bad or non of it go bad. I also had non of the "normal" signs of the core. Coolant smell, misty windows, damp carpet etc....

And I have learned more since my original post, since bringing it to the dealer and pleading with them that it was anything but the heater core:

*there is no water valve that "normally" is the culprit on this version of the 3 series

*After BMW said it was the heater core, last week or so I didnt believe them (see my old DME Warning post were the dealer almost "F" me out of 2k, I don't believe it was intentional) so I started calling local Indys...I told them the "tests" the other indy shop and BMW ha run and they agreed it was the core

*BMW said that a backflush of the core had never solved the problem and that it would cost 200-some dollars...the Indy shops, work on Bimmers are not experts IMO, and they all said a flush would fix it.

*I called the dealership back and said to do the flush as I already owed them 60.00 for there time, they said because of either the fluid or material inside the core (I don't remember) that it was extremely unlikely a flush would solve it as calcium deposits "grow" in the core and cause partial clogs that can't be flushed.

*I was sick of being cold and know the cost for heater core was 2k, as thought, "what the hell.". After the flush the dealership felt bad for me that it didn't work and charged me 150.00.

*I noticed a slight improvement when I turned the knurl knob, as in the past it did little to nothing, other than that, passenger side still cold, my feet still on fire and my vents/deferost are luke warm.

OK NOW ON TO THE REPAIR:

*There are 2 brands/models of cores that were used denso and valeo. They are both around 100.00 but was told that u don't know which one u have until u remove it. (I think that is wrong as I pretty sure I recall therealoem showing the 2 cores based on production year/month.

*I am patiently waiting for a DIY as I have been getting more PM on this problem from other members since starting it last year...also every member I have talked to resolved the problem by replacing the core...some did thermostat/water pump only to end up having to replace the core in the end.

*After talking to the SA (not the mehicanic) their was no mention of reprogramming. I would think if u fully disconnected radio, there may be something to "code" but not mention was ever made of that...they just said, "The parts are cheap, it is an expensive fix since the entire dash has to come out."

THAT IS ALL I KNOW, I AM WAITING FOR SOMEONE WITH A BIGGER "SET" THAN ME TO TRY IT FIRST AND POST A DIY.

IMHO, I am sure if u r a skilled mehicanic u can do it...the one concerned u alread mentioned is the "paperweight" possibility...not sure how close u live to a dealer but after doing the install if a tow to the dealer and 100.00 "coding" bill is the only extra cost I, personally would take that chance (and save 1700.00 or so in labor).....I am more concerned about getting to the core.

Keep posted as I would be more than happy to attempt this project together (virtually) on some weekend with pics/videos to each other and working through it.

GOOD LUCK

A side note, when I had the care in the dealer pointed out a small oil leak at the oil filter base....wanted 610.00 to fix it (others on this forum were quoted 800.00). Dealer said 4-5 hours of labor and 20 dollars in parts....I bought the gasket and fixed it in 2 hours or so....point being I don't think it is as difficult as the price implies.

Ok that was a long message to type on my phone..my hands are cramping



GOOD LUCK!! (I am not gonna double check this whole message for spelling and grammar so please forgive any mistakes..)

Thanks for the reply! I can ID the core by a tag visually located from the driver foot well, so that will not be a problem. I think I am going to just bite the bullet and "go for it"!

[335i101]

Zigsman,

Post a DIY and you would be a hero to the forum!

[e90n52b30]

Are you getting equal air flow on the passenger side vs the drivers side? I quickly skimmed through this thread on my phone, but have you checked to see of the ducting is broken?

Is it only blowing cold air when the car moving? Or does it happen with the. At at a standstill.

[335i101]

Originally Posted by e90n52b30

Are you getting equal air flow on the passenger side vs the drivers side? I quickly skimmed through this thread on my phone, but have you checked to see of the ducting is broken?

Is it only blowing cold air when the car moving? Or does it happen with the. At at a standstill.

Not sure if that was for me or zigsman....

I have good airflow, vents are as powerful as the drivers side (which is still throwing of heat)

[zigsman]

Originally Posted by e90n52b30

Are you getting equal air flow on the passenger side vs the drivers side? I quickly skimmed through this thread on my phone, but have you checked to see of the ducting is broken?

Is it only blowing cold air when the car moving? Or does it happen with the. At at a standstill.

I'm getting equal volume air flow from all ducts. The temperature is not dependent on speed; it is the same whether at idle or cruise. I've narrowed it down to two possible things...either a clogged heater core or a broken blend door. If I am going to go as far as removing the heater box to replace the blend door, I am going to replace the core while I'm in there since this seems to be a common issue with the E90. And I'll post a DIY whether it be with photos or video. But first, I am going to try a last ditch effort and attempt a back-flush if I find the blend door is not the issue. With the BMW diagnostic software I am able to send commands to the computer and can hear the door moving...so I think that is probably not the issue. That brings me back to the core

UPDATE:

I just finished with getting the new core installed. Much to my dismay, I found that you can actually have heat on one side and cold on the other because of the way the core is built. There are two tanks, one on top and one on the bottom. Fins feed water from teh top to the bottom, therefore, you can have part of the core clogged but not the entire thing. In short, changing the core fixed the problem.

I will be posting a DIY file with a bunch of photos shortly for all to enjoy!

SECOND UPDATE:

I finished the DIY with photos, look for it on the DIY forum.

[bateman1234]

@zigsman and 335i101 and others

Thank you all for posting, I've encoutered the same issue. It's winter here and the passenger zone blows just about 18 defrees C - a bit too cold to feel comfortable. This sounds much like your problem, but I do not feel like having the heater core replaced. Not only is that expensive, but also having 99% of my dash dismantled to pieces does not sit right with me. There's risk that after putting it back together there will be squeaks, cracks and play here and there in the dashboard which I definitely do not want.

So, after extensive search on the web (and this website) I have found the following things that COULD be done with this issue:

1. I can hear the blend door inside the dash moving when I push the buttons so this is definitely not the issue in my case. I can also hear another blend door moving somewhere inside when I change the passenger zone heating by a few degrees - although with no noticeable effect in temperature. Ergo - this is not the jammed blend door in my case.

However, if some of you suspect this actually IS some blend door in their case - a suggestion is to replace it (easy as that) OR use a bass guitar string to try to put it all the way down all vents, fiddle a bit and hope that miraculously you will touch the jammed blend door and release it.

You may also buy a USB interface to jack up to your BMW and operate the blend door from your laptop. It will let you see whether some of the blend doors are inoperational. This might set you back just about $50 on eBay.

2. Am I right thinking that PRESTONE FLUSH liquid or WYNN'S cooling system flush may help to clean the clogged heater core? Would that work? Or maybe it's better to connect compressed air to the cooling system and try to blow all the clogs away? Is this sensible? I mean - much easier than replacing the core anyway...

3. If, for some people, clogged air duct itself seems to be the problem - there is another solution. Some people mentioned connecting the ventillation motor with reverse polarity to try to reverse blow and clean out clogs in the ventillation ducts. Can anybody do a DIY? I have no idea how to make the motor work in reverse.


Can anybody confirm whether my ideas add up? I'm trying to find a way of repairing the issue without dismantling the dashboard altogether....

Regards.

[Surly73]

Curious: For those with clogged cores, what was your standard coolant replacement schedule (years/miles)?

[335i101]

Originally Posted by bateman1234

@zigsman and 335i101 and others

Thank you all for posting, I've encoutered the same issue. It's winter here and the passenger zone blows just about 18 defrees C - a bit too cold to feel comfortable. This sounds much like your problem, but I do not feel like having the heater core replaced. Not only is that expensive, but also having 99% of my dash dismantled to pieces does not sit right with me. There's risk that after putting it back together there will be squeaks, cracks and play here and there in the dashboard which I definitely do not want.

So, after extensive search on the web (and this website) I have found the following things that COULD be done with this issue:

1. I can hear the blend door inside the dash moving when I push the buttons so this is definitely not the issue in my case. I can also hear another blend door moving somewhere inside when I change the passenger zone heating by a few degrees - although with no noticeable effect in temperature. Ergo - this is not the jammed blend door in my case.

However, if some of you suspect this actually IS some blend door in their case - a suggestion is to replace it (easy as that) OR use a bass guitar string to try to put it all the way down all vents, fiddle a bit and hope that miraculously you will touch the jammed blend door and release it.

You may also buy a USB interface to jack up to your BMW and operate the blend door from your laptop. It will let you see whether some of the blend doors are inoperational. This might set you back just about $50 on eBay.

2. Am I right thinking that PRESTONE FLUSH liquid or WYNN'S cooling system flush may help to clean the clogged heater core? Would that work? Or maybe it's better to connect compressed air to the cooling system and try to blow all the clogs away? Is this sensible? I mean - much easier than replacing the core anyway...

3. If, for some people, clogged air duct itself seems to be the problem - there is another solution. Some people mentioned connecting the ventillation motor with reverse polarity to try to reverse blow and clean out clogs in the ventillation ducts. Can anybody do a DIY? I have no idea how to make the motor work in reverse.


Can anybody confirm whether my ideas add up? I'm trying to find a way of repairing the issue without dismantling the dashboard altogether....

Regards.

I found the flush did nothing for me except cost me money.

[335i101]

Originally Posted by Surly73

Curious: For those with clogged cores, what was your standard coolant replacement schedule (years/miles)?

I hadn't done anything yet, at the time the car was 2 year sold with under 50k on it.

I would recommend all to stay on top of this as coolant flushes every 30k is ALOT cheaper than getting a core replaced.

[zigsman]

Originally Posted by bateman1234

@zigsman and 335i101 and others

Thank you all for posting, I've encoutered the same issue. It's winter here and the passenger zone blows just about 18 defrees C - a bit too cold to feel comfortable. This sounds much like your problem, but I do not feel like having the heater core replaced. Not only is that expensive, but also having 99% of my dash dismantled to pieces does not sit right with me. There's risk that after putting it back together there will be squeaks, cracks and play here and there in the dashboard which I definitely do not want.

So, after extensive search on the web (and this website) I have found the following things that COULD be done with this issue:

1. I can hear the blend door inside the dash moving when I push the buttons so this is definitely not the issue in my case. I can also hear another blend door moving somewhere inside when I change the passenger zone heating by a few degrees - although with no noticeable effect in temperature. Ergo - this is not the jammed blend door in my case.

However, if some of you suspect this actually IS some blend door in their case - a suggestion is to replace it (easy as that) OR use a bass guitar string to try to put it all the way down all vents, fiddle a bit and hope that miraculously you will touch the jammed blend door and release it.

You may also buy a USB interface to jack up to your BMW and operate the blend door from your laptop. It will let you see whether some of the blend doors are inoperational. This might set you back just about $50 on eBay.

2. Am I right thinking that PRESTONE FLUSH liquid or WYNN'S cooling system flush may help to clean the clogged heater core? Would that work? Or maybe it's better to connect compressed air to the cooling system and try to blow all the clogs away? Is this sensible? I mean - much easier than replacing the core anyway...

3. If, for some people, clogged air duct itself seems to be the problem - there is another solution. Some people mentioned connecting the ventillation motor with reverse polarity to try to reverse blow and clean out clogs in the ventillation ducts. Can anybody do a DIY? I have no idea how to make the motor work in reverse.


Can anybody confirm whether my ideas add up? I'm trying to find a way of repairing the issue without dismantling the dashboard altogether....

Regards.

Of course I would try most of your suggestions before digging into the core...its a huge job! You can purchase a BT interface and software for you car (well worth the cost) which will allow you to individually activate all the blend doors via your laptop (and many other awesome features). I would recommend this cable and software to anyone with a BMW or MINI. If the problem IS a blend door, and by reading your post, it sounds like its not...replacing a blend door is just as in depth as the core. You need to remove the heater box from the car to do that...and the core sits right under the box, so it's really the same job.

A coolant flush is not going to unclog your core. It may loosen some gunk and free up a little bit of flow, but a clogged core is like a clogged artery...there is no real fix other than to replace it. I tried forcing pressurized water through the system, I tried compressed air...no luck.

I can say with confidence that you do not have a clogged air duct so reversing the blower motor in an attempt to clear the duct is a complete waste of time. The only reason your system will blow cold air is because either the heater core blend door is not actuating or the heater core is not getting hot (clogged, or heater valve inop).

Sorry dud...I may sound a bit pessimistic, but I've been in your shoes and been in denial! With the history of these cars and bad cores, that is most likely your problem. Your best bet is to find a good buddy willing to spend the weekend with you and do this yourself. It's a $120 part and two days worth of work. I don't live in an area where it snows, but I still cant go without heat! And I sure was not going to pay 2-3K to have the dealer do it for me.

If you have any questions about the DIY for this, feel free to ask.

[zigsman]

Originally Posted by Surly73

Curious: For those with clogged cores, what was your standard coolant replacement schedule (years/miles)?

I purchased my ride at 6 yrs old/120k and had all the maintenance records. There was no coolant flush done on the car but the water pump and coolant was replaced two months before I purchased. I will be doing a flush every 30-40k. It may cost a bit (fluid is $20/gal) but its worth not changing another core!

[bateman1234]

I've just noticed another problem with the heating. There's no heating for the passenger, but I don't really think it's the heater core problem. Although I can hear the blend door motors working when I switch buttons and turn knobs for the passenger, I don't think the door opens as it should because the blow of air from the passenger side vents is close to nothing when it's set to warm. When I set it back to cold, It blows with full power again.

This makes me think it's not just the heater core problem, but rather there is a master hot/cold blend door that opens for the passenger. Thing is, it still isnt possible to fix it without taking the dashboard apart.

Does anybody know what could be done to make the faulty blend door work again WITHOUT dismantling the car's dashboard? Does anybody have the air flow diagram of the heater box to let me know which door it could possibly be?

[335i101]

....this seems to be becoming a more widespread issue....good luck to all!!

[polaris_tr]

Originally Posted by 335i101

Ok, I just want to say that I have researched this topic extensively but I still have some questions.

Vehicle: 2007 335i Coupe 08/06 build date has Dual climate and Auto.

Problem: Regardless of heat setting the passenger side blows cool air. Defrost, vent and footwell. (It is distributing the air properly, but always cool) so, I have eliminated FSR.

Driver footwell extremely hot (I can manually make adjustments so thus isn't huge but maybe a clue)

Antifreeze/coolant down a little of the past 4 months, no visible leaks. I also performed the electric water pump bleed procedure and was able to get some air out of the lines.


HEATER CONTROL VALVE/WATER VALVE: this has been frustrating as at first glance I thought that would've the problem. However, I can't find this piece under the hood (or online as a part to purchase). I have taken off intake and there is a piece with three hoses going to it but not a "electric harness.". It had a part number and that came back to A/C condenser. I am starting to think that this piece is electronic now or is on the other side of the firewall. Since I can't find it I have not been able to test if this is the problem.

Thermostat: I have read that these cars have electronic thermostat, which I can't find for the life of me!?!? Also,if it was thermostat wouldn't I always get heat on the passenger side??

Heater Core: No smell of anti-freeze, no wetness in passenger footwell, or misty windows.

So here are my "uneducated guesses"...
1) Heater core is half bad and not distributing het to passenger side (maybe that is why my feet get crazy hot as well)??

2) Heater control valve is bad, but hidden or else I am blind??

3) Flaps / actuator not working properly? Like I said if I push the air goes to vent etc...but maybe there is a damper or flap that sends hot air over to the passenger side?!?

I kind of doubt thermostat as it is only blowing cool air.

Heater Core: can it go half bad? Or half clogged??


Before I get 10 responses about knurl knob, YES it is at red and YES I have turned off the "snowflake"


Thanks for the help. I will include a pic or two of the closest thing I can find to a heater control valve/ water valve.

https://mail.google.com/mail/s/?view...1&disp=attd&zw

@335i101

You wrote this about 3 years ago I see but I have some problem like your's.My is 2006 E90 3.20i and passanger side is not heat.Driver side is very hot.Did you fix the problem?If you fixed may you tell me how?
Thank you very much...