Steps required to remove and replace the heater core from a 97 BMW 318i sedan, with automatic transmission, basic multi-display and standard radio. Other E36 models will hopefully be very similar, though the earlier rotary-knob heater/AC controller will be substantially different in that area.
To replace the cabin air filter located behind the heater box, skip directly to Remove Glove Box, then Cabin Filter.
By twomanyprojects at Bimmerforums
Let me get this straight... You are swapping out parts designed by hundreds of engineers that get paid thousands of dollars for something you bought at Pep Boys because your buddy who doesn't have a job told you it was 'better'?!?
Christ Almight! Thanks.
Thanks!! You put some effort into this...
My radiator is broken i guess, some steam came out from my windshield on the passanger side a few days ago and wanted to check where the problem is...
Thanks again for this wonderful diy
My heater core is about to take a dump, Thanks for putting this tread up, your a scholar and a gentlemen!
some say.............
yeah mine definitely has a small leak, I'm burning a little coolant that I can smell. Will hopefully tackle this over the summer when I don't need the car every day.
Couldn't have done it without you, great thread! Advise: I started by removing the radio, & climate controls (before you unplug the climate control, turn ignition on and then turn the heat or A/C off, and uplug both of the connectors: this will save you time so you won't have to reconnect the battery and climate controls to move the vents out of the way when taking the heater core off). Do driver and passanger side panels first, then center console. Other than that, this guy has saved lots of time and money!!!
Can you get to the AC evaporator coil this way too or do you have to remove the whole dash like the bentley says?
Hi,
1) I am trying to replace the heater core for a bmw 325i 1992 model E36.
2) I pulled all the components out, centre conol, lower dash including the glove box..ect.
3) i am at a stage where the heater core is expose and ready to be pulled out.
4) I pulled the 3 pipes fromthe the side of the heater core but am having difficulty taking the heater core out! I followed your thread but cannot understand how to actually pull the heater core and header out when it is so tightly enclosed in the housing.
5) Would you haev any diagrams or pictures further than the ones you posted?
Thank you very much for your help
I changed mine from plastic tanks to aluminum tanks. Info is in this thread:
http://forums.bimmerforums.com/forum/showthread.php?t=1697929
Other advice for the DIY is to remove the car seats. The added room lets you stretch out instead of being in a cramped ball for many hours. What a time intensive nightmare.
Last edited by DaveAZ; 04-23-2012 at 02:40 AM. Reason: Finally installed mine.
dude this is a life saver! my heater core just broke on me yesterday on my way to work and two searches later i find this awesome post. You are the best!
http://bmwfans.info/parts/catalog/E3...or_wden_cable/
Last edited by Yadeezi; 08-10-2011 at 03:54 PM. Reason: Automerged Doublepost
I'm adding some here for those who might have more questions. Kevlar's link helped me a great deal. Just adding a few things that might help others with their heater core replacement.
REMOVING THE SCREWS TO THE FRONT OF THE HEATER CORE.
You can either remove the temp controls to get to the upper PITA screws or use a flexible screw driver. Magnetic tip will keep your anger in check too if you drop a screw. I went from under the temp controls to get to the upper screws and had the radio taken out.
REMOVING THE HEATER CORE. PLACING THE NEW ONE IN.
The only real issue with getting that damned thing out of there is the upper left lip where the tubes go into the core. There's a lip that goes around the core at tat area that you have to bend out of the way. Tying the tubes back so you know they aren't in the way. Then I used a small thin pry bar with a 90* bend on one side. Pushed that end over the top of the core and used another pry bar to bend the right side of the plastic out of the way of that upper section that is holding the core in. Came out pretty easily once I did this. Keep in mind you're prying against plastic so take it easy.
You're going to have to bend that same plastic out of the way to get the new core in as well.
O RINGS.
You need 4 smaller ones and 2 larger ones. 2 small ones and 1 larger one for each side of the tubes. Once you have the core out replace the O rings on the heater core side with a small piece of hard plastic to remove the old ones. The O rings tend to mend a bit to the tubes and using anything steel for this is asking for more leaks.
I also replaced the O rings on the engine side of the heater core tubes as well.
BOLTING UP THE TUBES TO THE NEW CORE.
It's very important you get these tubes lined up with the new core before trying to bolt them down. You wont be able to see the end of the tubes and if they are lined up correctly or not with their respective holes. So what I did was the following. Take each tube and push them into place. You can feel them move into place. Then get your flashlight and push the plate that bolts them down as far back as you can. If you can't see the mounting holes and the threaded insert (on the heater core itself) directly behind them, one of the tubes isn't lined up correctly. The plate should also look even and not pushed out on one side more than the other. If you can see the threaded insert just on the other side of the holes you're in good shape. Just make sure you tighten them in increments so you don't chance pinching any of the O rings.
My car is an early model but this may help others needing to do this PITA job. Good luck.
Would this guide help me in solving the issue with my car which seems to have very low air output?
They problem I have isn't that the heater or a/c don't work, more like its blocked and even on maximum fan speed it does not blow much air compared to my previous E36.
Kev try putting an FSU in, "Final Stage Unit" as its called. Sounds like your fan is only blowing on the low speed, mine did the same thing.
Last edited by shogun; 05-13-2021 at 06:52 AM.
just wanted to thank you for the post, i have two manuals including the bentley and your diy was clearly better than either,there is no way i could have done it without it, if i get a chance someday the beers on me, so thanks.
bump
I replaced my BMR and my fan is now blowing at speed but hot air only comes out of the two vents on the right of the cabin by the passenger. The other vents blow air but cold air. is this a clogged heater core, issue with the duct work, i.e. flaps, gates, etc., or something else entirely? thanks for any input in advance
thanks!
This thread is the reason I joined today. Will be attempting this next weekend.
Hey Guys
I have a slow leak in my heater core on my 92 e36. If I dont turn the heating on, does it mean that there is no coolant running through the heater core? Its starting to get cold here now, so was wondering if using the heater makes a difference? Does the hot coolant always run through the heater core, but the heat get deflected somewhere if you dont have the heater controls set to heat the cabin?
It does deflect water, but it mearly a butterfly valve and it doesnt seal completely. Your best bet is to either block the two hoses going into firewall or replace the core.
Last edited by shogun; 04-12-2021 at 11:32 PM.
Thank you so much! This DIY was one of the best I have ever seen and followed. I did the heater core on my 1997 318i yesterday and it went very well. I have the following little tips and ideas:
1) I didn't drain the coolant (gasp from the crowd). Instead I jacked up the back of the car and put it on jack stands at their highest. I also jacked up the front of the car and had it on jack stands at their lowest settings. This got me a few advantages. First all it made the heater core the high point of the system. I did suck the coolant out of the expansion reservoir, but I bet even that was not necessary. When I disconnected the 3 pipes from the core I expected a gush but I just got a few dribbles. The second advantage was that it made everything more accessible and comfortable to get at with the car higher up.
2) I took out both front seats. 4 bolts each and a few connectors. Then I covered the floor with thick moving blankets and had a real soft comfortable workplace, and was able to very comfortably lay on my back and work on the panels and fiddle with those three bolts holding the pipes to the core. I also laid blankets on the floor outside the car and had more comfort for another work position.
3) I missed the tip about getting the flaps to lay flat and fiddled with that for a long while. To reiterate a prior post, put the climate controller in manual mode, turn off the air supply to the feet (thus closing the flaps) and then disconnect the wire going to the little motor on the right side of the heater box that controls those flaps. If you don't do this then when the car is turned off they automatically revert to a partially opened position. Very infuriating until you figure it out.
4) I put a little silicone brake grease on the o-rings. Silicone is good for rubber components, and I figured it could handle the heat.
5) I took the glove box out with it attached to the air vents above it. You still have to take out all of the bolts, but they slide out together as a package very nicely. This also prevents glove box sag from creeping in if you don't have any already.
6) I cleaned the evap with a spray cleanser while it was so nicely exposed, then blew out the system with the cabin air filter removed and got it all cleaner than it has ever been.
7) I filled the core with distilled water before I put it in to reduce the amount of air that would need to be bled.
8) Once the core was in I let the back of the car down on the ground, making the bleed screw on the radiator the high point of the system and ran the car with the heater on full blast and bled the air. It all went pretty fast.
And now.... no smell of coolant in the car, no foggy windshield, hooray!!!!!!!!
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