HELP! - Cannot find heater core replacement!

[ThirdPedalNirvana]

Well it's been 5 months since I started disassembling the interior of my 1984 533i to get to the leaking heater core, and I finally did it! The heater box is out! (It probably would have gone faster if I wasn't going up to Tahoe to ski 3 weekends a month). Now my car is disassembled, tarped because the rainwater will get into the cabin through the gaping hole in the firewall where the heater box used to be, and my (FUNCTIONAL!) AC system is removed, capped, after having the refrigerant safely reclaimed.

I waited on ordering the heater core because I needed to confirm if it was Behr or Sofica. It's Behr.

And NOW... with the car in pieces and my memory of how those pieces go back together fading... I discover that NOBODY- no websites, no dealers, NO ONE has any Behr heater cores for my car. Every website that shows availability for part number 64111466217 or part number 64111366680 is lying - I've called them all and they tell me "this item is backordered and we have no idea when it will be available".

To make matters worse, I am hoping to sell my house and move sometime in the next 6 months. Can't rightly do that with my car disassembled and the garage full of parts.

Does anyone have any idea where I can get a heater core? I don't rightly care about price anymore... I mean I'm probably going to pass if it's over $1000 but short of that... I'm desperate.

[beaseac]

Not sure if this is an option or not but you can probably take the old heater core to a radiator shop to be recorded... Or repaired.

[ThirdPedalNirvana]

Hmm... didn't consider this. I guess if the issue is with the metal it can be rewelded, I sort of figured it must be leaking from the plastic.

I'm in the south SF bay area so if anyone has had any experience with this local to me, please chime in!

[Mike W.]

Not sure if this is an option or not but you can probably take the old heater core to a radiator shop to be recorded... Or repaired.

The plastic on the plastic tanked heater cores usually fails before the aluminum core. I don't know where OPs is leaking but I would not do that.

Does anyone have any idea where I can get a heater core? I don't rightly care about price anymore... I mean I'm probably going to pass if it's over $1000 but short of that... I'm desperate.

Not holding my breath, but I found the following. The prices are in AU $, so while not cheap, not as expensive as it appears on first glance.
https://www.ebay.com/itm/324157182308?f ... BMxKKNpuVh

And this one which is probably even less likely, https://x-ph.com/bmw-hvac-heater-core-m ... 111366680/

And this, https://www.wpdusa.com/products/40328/2 ... 66680.aspx

I'm pretty good at finding stuff and it looks like slim pickings. Good luck and keep us posted if you do find one! There's also a place in England which shows several manufacturers, at very good prices, but all out of stock. Dunno if that's discontinued or out of stock until someone orders one.

Maybe hit up Ivo, he's got a place in NL that specializes in BMWs, and he might be back now from St Paddys day in SD.

[ThirdPedalNirvana]

I will inspect the heater core tonight and see if I can see any holes in the metal, otherwise I think you're right, it's probably seeping from the plastic end tanks. It wasn't a *BOOM* your floor is covered with water type of heater core failure, more of a "huh, where is my coolant going when I park it for a week" and "why does the defogger make the window foggier at first" and "what's that smell" sort of heater core failure.

I actually already have been in contact with the eBay seller from Australia, very friendly and responsive people - they checked the part numbers and confirmed it is a Sofica heater core, not Behr. I also already talked to WPD - they checked with the supplier and that part is NLA. They told me they'd fix their website within 24hrs to not show the part anymore.

I will try to get in touch with Extreme Power House and see if they can confirm they have the actual part. Thanks for finding that one!

I've also heard/read about people making the Sofica core work in the Behr box and vice/versa, maybe that's an option?

[ThirdPedalNirvana]

The prices are in AU $, so while not cheap, not as expensive as it appears on first glance.

I'd be thrilled to find one for under $300. I was expecting the prices to be $300-$400 for genuine OEM BMW, I've had enough time to save up over the course of the project. I know there are people on here who are like "heater cores shouldn't cost more than a radiator", but as far as I'm concerned, getting to buy OEM parts for a 40 year old car is a privilege, especially considering I can't stand how modern cars drive. (It's hilarious to me that my newest car is currently as old as my Volvo 850 was when it was given to me because it was the 'old' car)

[Mike W.]

I've also heard/read about people making the Sofica core work in the Behr box and vice/versa, maybe that's an option?

I don't know. Apparently one or both of the blower motors can be made to work in the opposite, cores I haven't heard of. If the Sofica is just smaller and they might be able to provide measurements, stuffing a little more foam in there would be no big deal.

If you weren't already this far, I'd have suggested using a little bit of radiator sealant, not a whole bottle, just a little. I limped my E28 like that for 100K before it just wasn't quite sealing up, and the first time I tried using the defroster, it completely fogged up the windshield, I mean bad. But since you're this far in I wouldn't want to put the old one back in and hope.

There is this place, https://www.buycarparts.co.uk/bmw/5-e28 ... 5B0%5D=467 which shows out of stock, but multiple brands and cheap. Probably vaporware, but maybe it's just not a stock item. Also check with Ivo.

I know there are people on here who are like "heater cores shouldn't cost more than a radiator"

It doesn't matter what it should cost, at 40 years old much of it comes down to can I get it.

[turbodan]

I fear the day that I need an e28 heater core. Like death, this situation will come for us all and no one knows how or when. Considering parts availability, I have been pondering a few options. Option number one which may be the most viable would be an electric heater core. These are available aftermarket or from various hybrid and electric vehicles. Step one is find one that fits, and I haven't done anything with that yet. If you have the core out, take some measurements of the rectangular dimensions and we can start exploring options. I like this idea as it removes the coolant from the cabin entirely. It may not offer as much heat but if I wanted to be most comfortable I would probably drive a different car.

Option number two is to fit a different radiator in place of the stock core. What crossed my mind was a motorcycle radiator. If it can fit in the box, it can probably be made to work with some changes to the lines and connections. Heat output will likely be reduced as these aren't as densely finned as the original heater core. As long as it takes the chill off and defrosts the glass though, it's good enough for me.

[ThirdPedalNirvana]

Well, this isn't encouraging.

I fear the day that I need an e28 heater core. Like death, this situation will come for us all and no one knows how or when.

This might be an absurd statement because I'm 32, but I was always hoping that this BMW wouldn't die before I do. After a decade and a half of every single car on the market being unacceptably numb, digitized, and uninvolving to drive, I've lost hope that I will ever like any new cars again. Ironically the only new cars I sort of enjoy driving are electric, but I can't stand how festooned with touchscreens the interiors are. I am as big a fan of Star Trek TNG as anyone is, but I'm driving a car, not piloting a starship.

I did check with all the websites which show availability and they all report that they have none and have no idea when they will be available. How long has this been an issue for E28's? Have heater cores been unavailable for a decade? Or did I just happen to luck into needing one when they were all gone?

As much as it would be a bummer to not use the car in the winter, I am from California so I could probably live with it... IF the AC could blow at the windshield - but it can't. I'm not comfortable with the idea of having no windshield defogger, as I need to use them almost every day on the ocean side of the mountain range.

Option number one which may be the most viable would be an electric heater core. These are available aftermarket or from various hybrid and electric vehicles.

This is an interesting proposition, but one I'm not entirely comfortable with. First of all, I see no way to control an electric heater from the OEM panel, and I'm not about to just put a toggle switch in the dash. I only got my heater valve working properly less than a year ago. Secondly, this is making a major change to the load on the electrical system. These aren't exactly 60's Ford Falcons, I wouldn't presume to understand the wiring well enough to know I wasn't setting myself up for electrical failures or damage to any of the computerized components. At the very least I'd want an uprated alternator to go with it.

If you have the core out, take some measurements of the rectangular dimensions and we can start exploring options.

I really appreciate this, at the moment I do not have the core out. I tried to take the box apart yesterday, but got cold feet. I'm not entirely clear on how it comes apart, there is a screw that is stripped in place (i can't get it out), and i'm afraid of breaking the plastic. My mechanic who drained the AC system for me has been discussing options with me and is willing to help me get the box apart and see if we can make the Sofica unit fit, so I'm not going to mess with it until I bring it to him. If we can't make a sofica unit work, I won't have him reassemble the box, and I will be able to report on the dimensions.

Option number two is to fit a different radiator in place of the stock core. What crossed my mind was a motorcycle radiator. If it can fit in the box, it can probably be made to work with some changes to the lines and connections. Heat output will likely be reduced as these aren't as densely finned as the original heater core. As long as it takes the chill off and defrosts the glass though, it's good enough for me.

I agree that I won't be broken up if the heat output is reduced. So long as it can deliver at least 50% of the heat the original heater did, I'm sure I'll be fine...

which leads me back to Sofica. Unless the Sofica unit is too big - which all research seems to suggest it is not, I imagine it's much easier to adapt it to fit my heater box than it would be to adapt a motorcycle radiator.

[Mike W.]

Turbodan is a bright guy, so I can't automatically dismiss what he says, but basic numbers are 3BTU per watt, I believe the heater is somewhere in the neighborhood of 17K BTU, so you'd be looking at ~6Kw to match output. An 80 amp alternator is 1120 watts so if you used 2/3 of it you'd be at ~2.2K BTU.

I suspect electric cars use some variation of a heat pump which is roughly 3X as efficient as resistive heat. But that's a whole additional refrigeration system, which I don't see as viable.

How to find dimensions I have no idea, but I think the solution is either the Sofica one or one from something else with similar dimensions. Might even be someplace that supplies domestic collectable cars with heater cores and that might have searchable specs. Might.

To me, taking the box apart was easy compared to getting it out. Theres a bunch of clips that hold it together. You have to be careful, but getting it out is the hard part.

[ThirdPedalNirvana]

I suspect electric cars use some variation of a heat pump which is roughly 3X as efficient as resistive heat. But that's a whole additional refrigeration system, which I don't see as viable.

I'm actually an HVAC engineer for commercial projects, so forgive me for pulling out my soapbox:

Every EV SHOULD use a heat pump system... but automakers see it as an "upsell" they can put on the more premium models, because it greatly reduces the drag on your EV range when the heater is on. But it's silly to use resistive heat in an EV. Every single AC in the whole entire world is technically a heat pump. The only physical difference between "cooling-only" and "cooling or heating" is whether or not the system has a reversing valve in it. You don't need another refrigerant loop, or another heat exchanger, or even another thermostatic expansion valve. You only need a reversing valve that turns the evaporator into a condenser and vice versa (and a controller that understands how to operate in both modes). I predict in 10 years, nobody will be using resistive heating elements in EV's anymore. In fact, on the DX split system market (ductless AC's) every manufacturer has dropped their cooling only models in the last two years. You can't even buy one for an electrical room or a server room - you have to get a heat pump even if you'll never put it in heating mode. THAT'S how trivial a cost it is to add a reversing valve to a product.

EV makers putting resistive heating elements in the car at ALL is just them being deliberately obtuse. The only drawback of a heat pump system is that it doesn't work when the outside temp gets about 15 or 20 degrees below freezing - in which case the solution is to add a resistive heating element to the outdoor heat exchanger. It makes more sense to me to upcharge for that option as a "cold weather package" that yuppies who don't really need it will shell out $2k extra for because they drive up to Tahoe twice a year. (And of course anyone who lives in REAL winter will buy... assuming they want an EV at all... When you live in northern Minnesota, the 70% of the energy in the gasoline that gets lost to heat is not "wasted energy", and the 4 million drivers in Minnesota are only 2% of the drivers in the US)

That said, many EV's currently do use resistive heating elements. But most EV's make more than 200hp - that's 180kW, or roughly 100x the power output of the most powerful heater you can run off a standard 15A outlet in your home. So it is no wonder why EV's can heat themselves with a simple resistive heating element.

To me, taking the box apart was easy compared to getting it out. Theres a bunch of clips that hold it together. You have to be careful, but getting it out is the hard part.

Frankly, you're probably right. I am sure that it is easier to take apart the box than it is to remove it from the car... but that's probably why my mechanic volunteered to get it apart for me and help me fit a different core, yet funnily enough didn't volunteer to remove the heater box from the car free of charge

[ThirdPedalNirvana]

I've potentially found a "hail mary" option. I could take a 3 hour drive down to Paso Robles and see if Brassworks can make me a custom heater core. The lead time will probably be painful, but this would only come up if the Sofica core is a no-go.

If the Sofica core works, I will take lots of pictures of the heater box assembly and post here for posterity.

[Mike W.]

I suspect electric cars use some variation of a heat pump which is roughly 3X as efficient as resistive heat. But that's a whole additional refrigeration system, which I don't see as viable.

I'm actually an HVAC engineer for commercial projects, so forgive me for pulling out my soapbox:

Every EV SHOULD use a heat pump system...

Didn't mean to talk down to you when you know more about it than I do, but there's so few here that would know about that stuff...

But the electric cars are using resistive heat? Cheap to do, but dumbfounding.

[4DSC]

Nirvana, did your quest ever come to a conclusion? Curious to hear if you figured out a solution. I've been in a similar boat for a while trying to find an original Behr. I believe they were available up to 3-4 years ago. I tried ordering one from ECS a few years ago when it was backordered during covid and they finally got back to me later saying it was now NLA. Same with a BMW dealer that had it listed as available. There are a few random ones available on ebay now, they seem to rotate in and out of there. No idea on quality, but if anyone else has tried or is familiar with the "Thermotec" brand, I'd be interested to hear any feedback: https://www.ebay.com/itm/276217749457

[Mike W.]

I wouldn't hold my breath, but the link says they're in stock. And we all know, nothing on the internet is ever wrong.

https://www.buycarparts.co.uk/thermotec/16264126

[4DSC]

I rolled the dice and ordered this one: https://spareto.com/products/thermotec- ... g/d6b019tt

At $65 shipped it was worth trying. If it arrives, I will report back with pictures. Though I don't have a real Behr one on hand to compare it to for outward quality or dimensions/fitment.

[4DSC]

The Thermotec heater core arrived from Estonia in under a week which was pretty impressive. As far as quality, unfortunately I don't have any OEM cores to compare it to on hand, and it will probably be quite a while until I install it, so I can't say. It _looks_ decent? Plastic pieces feel OK. No way to know how it would hold up over years. I took some pictures with measurements in case it's helpful to anyone else considering going this route. Thermotec D6B019TT. Full res album: https://imgur.com/a/1OYrrvt

[M Blitz]

Unfortunately, I'm in the same boat as you. How's the Thermotec heater core performing. Would you buy it again?

[4DSC]

I haven't installed it yet, sorry. My leak seems to have "self healed" for the time being so I'm saving the job until I'm ready to do some other involved items like the dash. Ordered it mainly to have it around for when I'm ready, as at this point I'm worried even these aftermarket options are going to disappear.

[4DSC]

Bringing this thread back from the dead as I'm getting ready to dig in and finally replace the heater core. Will report back on how the Thermotec compares dimension wise and anything else I learn.

I have a question for the group -- this may sound kind of dumb, but given how much of a pain getting to the core is and only non-OEM parts are available now, I was contemplating how to increase my chances of making this core last a while. I understand the plastic tubes/housing are a failure point from fatigue after many, many heat cycles. What if, now hear me out, I pre-coated the plastic bits in, say, some kind of silicone sealant before installation? Or some kind of epoxy? Bad idea? Worth a shot? Would doing this actually maybe negatively impact the longevity of the plastic instead?

Thanks for any insight.

[Mike W.]

I think heater cores are typically 200K+ mile items. Mine was leaking when I bought it at 175K, but I limped it along for another 100K. I had to do one on an E23, similar era BMW and it was at around 275K. I know you want it to last forever, but do you really anticipate more than 200K miles? E39 radiators run some 30F hotter than E28s and still last 100K. I wouldn't try to do anything to the core itself, but if you're really worried you could use a 75C or 71C thermostat to keep it a little cooler. Might lose a little MPG but it might be a little easier to pass the Nox component of smog tests.

[4DSC]

I'd be perfect happy if it lasts 100k. My main concern is with the unknown parts quality on this replacement brand. I wouldn't be surprised if the plastic isn't up to the quality of an OEM part and just thinking of ways to get ahead of that and maybe reinforce it while I'm in there. Interesting idea on lowering the temp of the system overall, though. Probably overthinking it, but figured it was at least a question worth posing.

[funkycharms]

After months of hunting and dead ends, I was able to track down a thermotec heater core as well - hopefully it fits no issues. The vendor i purchased from said they may have one or two left in their inventory.

The Thermotec heater core arrived from Estonia in under a week which was pretty impressive. As far as quality, unfortunately I don't have any OEM cores to compare it to on hand, and it will probably be quite a while until I install it, so I can't say. It _looks_ decent? Plastic pieces feel OK. No way to know how it would hold up over years. I took some pictures with measurements in case it's helpful to anyone else considering going this route. Thermotec D6B019TT. Full res album: https://imgur.com/a/1OYrrvt

[4DSC]

Good news on the Thermotec. Got around to doing the heater core this week and I am happy to report that it was an exact fit. It does feel a little less high quality as far as the fins go than the Behr but I'm just speculating. Hoping it holds up for many years to come.



Why the heck do they use plastic for the pipes on the side? How much more could it cost to just make it all metal.