Heater Core Replacement - Pipe issue/question

[JThomp33]

So it's getting colder in the NE area, and I've had a replacement heater core for the 540i/6 for almost 2 years now. I felt it was time to tackle the project. I was having the typical symptoms: Fogging up the lower inside of the windshield, strong coolant aroma when the heat is full blast, etc.

After removing the center console, OBC/radio/Temp control unit, and other various items, I came face to face with the damage:
**** The thread: https://www.bimmerforums.com/forum/s...HKA-content)is a great resource for most steps ****

Heater core car .jpg

Using a T20 screwdriver (and some needle nose for the hard-to-access area for the top left pipes), and bending the aluminium pipes, I was able to wriggle the core free:

care removed.JPG

Now comes the start of what is now the issue - the issue I was unable to find an answer to in the Bentley/Hanes manual, searching forums, and utilizing - https://www.bmwtechinfo.com/repair/main/741en/index.htm (Or I missed something )

.........removing and replacing the pipes .

I hacked up one of the pipes during the removal of the unit, and thought I could removed them easily. I disconnected the hoses beside the heater valve on the outside of the fire wall, and tried to pull the hoses through. No luck. I hacked up the old foam gasket closest to the core that blocks the cabin from the areas behind the dash. Still nada.

I realized there was a clip down on the inside of the fire wall - so I removed that:

Pipes firewall.jpg

I was able to get all of the pipes out, but it was a royal PITA !

dead core .jpg

Hindsight is 20/20. I bent each pipe (multiple times) in order to remove them from the small crevice behind the dash. I am now doubting I can complete this task and fish all of 3 replacement pipes (Ideally attached to the replacement core) through the small (and awkward dash hole) - properly fit the foam gasket into the hole, and then push each pipe back through the firewall.

My question is - has anyone else with a 540i replaced their pipes when doing the heater core? Or am I screwed/in over my head?

Any input is much appreciated!

[jehu]

I heard tell of the horror of fitting these pipes through into position... I have done heater core replacements on these about 4 times and managed thankfully never to need to replace the pipes.. i still have several sets of them..

I just did this job and thought I might need to do the pipes because I was having a hell of a hard time getting that side plate to drop into its slot and thought I had bent one of the pipes or the plate itself but I eventually managed to get it in using some locking pliers holding it to the unit.

I wonder if you would have to remove the actual dash top itself..

One thing I found helped me tightening that side bolt was an 8mm ratcheting wrench with a swivel . like this https://www.lowes.com/pd/Kobalt-8mm-...SABEgLYMfD_BwE

[zubbie]

Feel your pain. Replaced my core some years back but still have a leak as a result of misaligned / bent pipes. I'm not sure how you replace a core without bending them.

Have been putting off the fix and now I know why. Hopeful someone has an answer.

[demetk]

IIRC, I unbolted the vertical dash support beside the steering column and bent it out of the way to provide more clearance.

[jehu]

Juts by being as careful as possible and only moving them just clear enough to move the core.. the rubber grommet will allow enough movement without bending them... I slid a wide flat head screwdriver blade to pry out the side pipes just enough to then slip in another flat metal piece like a pocket knife blade so the pipe didn't slide back in then freeing the front pipe and carefully pulling it up and over so you can pull out the unit.

Feel your pain. Replaced my core some years back but still have a leak as a result of misaligned / bent pipes. I'm not sure how you replace a core without bending them.

Have been putting off the fix and now I know why. Hopeful someone has an answer.

[bagekko]

Ugh why you reminding me... swear on my first E34 removing the pipes and putting back in took more time than the rest of the job. I did it without bending but it aint easy. My current E34 needs a HC soon and I will be reliving the nightmare hopefully after winter....

[JThomp33]

All,

Well I was able to get the pipes in, and surprisingly it only took 30 minutes to an hour. I marked each pipe with a sharpie 1-3, and then used painters tape to wedge all 3 into a triangle shape, and did some maneuvering. Demetk was correct- removing the support brace would make the job easy- two 13mm bolts on either side and two Allen bolts behind the steering wheel. I was able to remove 3/4- instripped one of the Allen bolts (and bent an Allen key) because it was seized in there pretty good.

I have not had any time to put the dash back together so I have been driving to and from work with an exposed heater core, but after 50 miles- no leaks and all good!

I'll post photos later

[DarienFalks]

I just did this job myself and didnt have to replace the pipes. I used a screw driver it pry the pipes on the left into the heater core and was able to get it bolted down just fine. Dont forget to zip tie some of the cables back up or your heater control cables will hit them.

[JThomp33]

I have been delaying putting the center console and instruments back together for 2 reasons: 1- the climate control bulb I was sent from BavAuto was incorrect though the part #'s match up (#10 in the diagram on realOEM) below:

http://www.realoem.com/bmw/enUS/show...diagId=64_0566

#2 - and more pressing. I noticed one of the "vents" - left side - behind the core - had a broken arm from the top left of the flap and it sags to one side. I searched on RealOEM and cannot find a replacement part. See photos below:

Broken vent .png

Here is a close up:
Vent.JPG

Should I be concerned if this has the potential to fall behind the core?

Any input would be great!

[m60power]

Is that vent opened by a stepper motor or servo, or is it "passive"? It looks like there is a weight bar on it so it may open just from the blower airflow; if that's the case you could probably just remove it. If that vent is the air path to the heater core it may only open via a motor when the temp dial is turned to hot.

Edit: Now that I think about it, those vents might be the mixing flaps to adjust the amount of air that gets heated by passing over the heater core. If that assumption is true then turning the temp dial to anything warmer than the outside air temp will cause the driver's side heater valve to open, and therefore the driver's side air to be full hot if the that vent flap is removed. I wonder if there is an airflow diagram for the e34 IHKR system?

[5mall5nail5]

I can't imagine doing this job - ugh

[m60power]

I can't imagine doing this job - ugh

I've always said replacing the heater core is where I draw the line for e34/e32s I've owned. Either I live without heat or scrap the car Knock on wood I have yet to have one fail.

[JThomp33]

Not terrible just tedious and lengthy. Ran into you on 611 a year ago near valley square shops in warrington- black 540. Your 525 spooling up is one hell of a sound

- - - Updated - - -

I've always said replacing the heater core is where I draw the line for e34/e32s I've owned. Either I live without heat or scrap the car Knock on wood I have yet to have one fail.

Is that vent opened by a stepper motor or servo, or is it "passive"? It looks like there is a weight bar on it so it may open just from the blower airflow; if that's the case you could probably just remove it. If that vent is the air path to the heater core it may only open via a motor when the temp dial is turned to hot.

Edit: Now that I think about it, those vents might be the mixing flaps to adjust the amount of air that gets heated by passing over the heater core. If that assumption is true then turning the temp dial to anything warmer than the outside air temp will cause the driver's side heater valve to open, and therefore the driver's side air to be full hot if the that vent flap is removed. I wonder if there is an airflow diagram for the e34 IHKR system?

It's passive and I DO NOT want this vent to fall and land behind the recently installed heater core (for obvious reasons). I may carefully remove it and then apply a 2-party epoxy dab to the top left and "fabricate" / sand a new tab to hold it in place when installed

[5mall5nail5]

I've always said replacing the heater core is where I draw the line for e34/e32s I've owned. Either I live without heat or scrap the car Knock on wood I have yet to have one fail.

My '95 525 that I just dumped at the dealer for my F30 (kind of wish I had planned better, had a 40% LSD, M5T n'ring suspension, EMP water pump, etc. on it) would leave a puddle of coolant on the ground about 1 - 2" diameter ONLY in the winter. I came to the conclusion that it was from the heatercore in winter when I'd use heat. The drops were right around where the "frame rails" form on the unibody underside, I think it was dripping inside the cabin and then out some drain hole. The carpet would slightly damp sometimes. Not my prob now

[m60power]

My '95 525 that I just dumped at the dealer for my F30 (kind of wish I had planned better, had a 40% LSD, M5T n'ring suspension, EMP water pump, etc. on it) would leave a puddle of coolant on the ground about 1 - 2" diameter ONLY in the winter. I came to the conclusion that it was from the heatercore in winter when I'd use heat. The drops were right around where the "frame rails" form on the unibody underside, I think it was dripping inside the cabin and then out some drain hole. The carpet would slightly damp sometimes. Not my prob now

Haha! Not to derail the thread, but how do you like you f30? As in the driving feel, build quality and whatnot? Does it have the B58 motor?

[5mall5nail5]

Haha! Not to derail the thread, but how do you like you f30? As in the driving feel, build quality and whatnot? Does it have the B58 motor?

Has the N26 and ZF 8HP. It's... awesome. I went RWD vs. xDrive. Plenty of zip for a daily. Sport trans program shifts savage when you want. It's awesome.

[JThomp33]

So no one has experienced this, and follow up, has an E34 being parted out so I can acquire a new vent (assuming they're the same across all models).......

[m60power]

So no one has experienced this, and follow up, has an E34 being parted out so I can acquire a new vent (assuming they're the same across all models).......

I did some searching and couldn't find anymore info about those two top vents on the IHKR unit. Check the classifieds sub-forum whole parts car section. Someone is parting an e34 525i.

[Ed Courter]

One error I have made, is forgetting to remove the old O rings when working backwards and up side down. Some leaks, had to re do following year.