Heater core replacement

[rajah996]

Thank you for the quick reply. I assumed that is what was meant in the pic, but I just wanted to be sure.
My car has turned to be quite the project.... but I am enjoying the process bc
of the accomplished feeling at the end of the day when everything works right.

[SETITOFF]

Can the heater core, heater pipe or seals fail and NOT leak coolant inside the car? I have a coolant leak that seem to be in the middle under the car in the area of the shifter. Coolant does not leak into the car.

[ByMW]

Can the heater core, heater pipe or seals fail and NOT leak coolant inside the car? I have a coolant leak that seem to be in the middle under the car in the area of the shifter. Coolant does not leak into the car.

Yes, the coolant can drain from under the heater core into the transmission tunnel. There are drainage tubes specifically for that reason.

[Bluesman]

Can the heater core, heater pipe or seals fail and NOT leak coolant inside the car? I have a coolant leak that seem to be in the middle under the car in the area of the shifter. Coolant does not leak into the car.

Might also want to look at the heater valve as it sits right above the center of the car on the firewall.That was where I had my leak.

[Rich in Boston]

The auxiliary water pump which is just below the heater valves is also a common leak point. Those plastic necks get brittle after all those hot and cold cycles, just like those infamous BMW plastic radiators.

[sleepy81]

It is not that simple. What is not shown in these pictures are both driver and passenger side dash support tubes which run from either side of the top of the dash towards the center console and down in front of the heater core cover. It is the tubes that prevent the heater core from just coming off. Either the EURO cars don't have this (doubt it), or the tubes were taken off the last time someone was back there to apply all that epoxy gooo to the double black tube you see in the pics.
You can do the core exchange without taking out the dash, but for the rest of the 8 population, it is more work than what is shown here. I have it down to about 4 hours from start to finish (I "modified" my dash supports to be able to just unbolt the piece that is in the way)..

Nice write-up though...

I may have bitten off more than I can chew. This is my second day at it after the sweet smell with the heater on. Strange thing is I have yet to see any leaks.
Anyway, I have both tubes as TxGR8White mentions and cannot see any way to get the cover out. The tubes prevent a straight pull out & the two top motors prevent upward movement.

[8eights]

I'ts just time consuming, Done it 5 times, Took the dash out for each car, Puts everhthing in clear view and very easy to change things this way in my opinion, Plus my hands are too big to fiddle with what i can't see, The core and pipes are easy to align and the cusihioning foam is simple to replace in the correct locations with it all apart, I would'nt do it any other way because it's a must get correct the first time as i hate it! I'd much rather pull the heads off or replace the engine!!!)

[lihp321]

The only way to get at that top left clip is to remove the cluster. What a pain. I did the evaporator and expansion valve as long as I was down there.

[sleepy81]

Well, I'm going in thru the top although I expect dash, cluster, & steering wheel removal to be a challenge first time. THERE IS NO WAY TO DO THIS THRU THE CONSOLE WITH TWO BARS. The LH bar supports the passenger air bag. (RHD).

[DemonW90]

Take 15 more minutes of time and you'd have the whole dash out and a ton more room to work with seems like a waste to try and go through the loop holes of pulling it out that way

[cartoonz]

early cars don't have the bar on the passenger side... did those come in with the 2nd airbag? What year?

Even on the early cars, at least in the USA, there is more in the way on the driver's side than on the OP's car... hence the comments about pulling the cluster. You can do it without exactly removing the cluster or even unplugging it, but that last clip on the driver's side is a b*tch to get to. Seems there is a massive knee bolster over here that did not make it to Croatia

[Max Lumens]

There are bars and knee bolsters on virtually all the US cars, regardless of airbag status. The bars have brackets welded on them to hold the bolsters, which makes it that much harder to work around them. Euro design is nominally cleaner, but I believe I'd still pull the dash, if only based on Tom's experience, since I've never done one as a simple R&R myself.

[cartoonz]

the early cars just had the bars on the driver's side, I *think* this changed with the addition of the passenger side airbag in the upper glove compartment location.

But the early USA cars DO have a gnarly knee bolster that Duje's car does not, and this makes his procedure a pain in the @ss... but it does work - I did it today

[Max Lumens]

You're right; I recently took apart the glove box on a 91, should have remembered. The funny part is that the knee bolsters are a DOT requirement; maybe it took effect later on the passenger side.

[daanens]

Duje....Is there a difference between the Euro 8 versus US model. I see some comments about this in the treads.

Daanen

[JTM850]

Pulling up this thread again.

Is there a easy way to determine if my heater core is busted or not?

I have coolant smell in my cabin when hot air is coming out of the grills when engine is warm. Temperature is set to normal. Floormat is not wet, and there is no coolant smell when the car has been cooled down completely. My Aux water pump burns the fuse every time car wants to use it, so i have to replace it.

[peezen]

This usually means that you have a leak in your heater core. The leaks are usually so small, like a drop at a time, that it evaporates and comes out of the vents rather than spilling into the foot wells.

The coolant smell when the heater is on is a sure sign, and you wouldn't get the smell when the car is cold and off because there isn't coolant circulating in the heater core, nor is it hot enough to burn it off and send the evap through the vents.

The good news is that it doesn't look like to onerous of a job!

[8eights]

+1

[JTM850]

This usually means that you have a leak in your heater core. The leaks are usually so small, like a drop at a time, that it evaporates and comes out of the vents rather than spilling into the foot wells.

The coolant smell when the heater is on is a sure sign, and you wouldn't get the smell when the car is cold and off because there isn't coolant circulating in the heater core, nor is it hot enough to burn it off and send the evap through the vents.

The good news is that it doesn't look like to onerous of a job!

Oh Balls! Fix something and then something else breaks. I'm losing my mind... If you own 8, then prepare to have a second car to drive...

Thanks anyway... So a new heater core and pipes + o rings? My old one is original...

[Ferns8]

Get write up. If I ever need to replace mine I'll refer to your post. However in SoCal we hardly ever use our heater. It should be almost like new.

[cartoonz]

haha... Fern wishes

[tvjake2]

Get write up. If I ever need to replace mine I'll refer to your post. However in SoCal we hardly ever use our heater. It should be almost like new.

We don't use the heater...we use the seat warmers instead.

[sleepy81]

I had the sweet smell when the heater was turned on but it was the A/C Evaporator leaking. See the purple photos http://api.viglink.com/api/click?for...Con-leak-found

[JTM850]

I am now ready to do the job. I bought new heater core (BEHR) and it came with all the needed O-rings inside the package One question still remains:
Do I have to drain some of the coolant from the system before I begin?

Edit: Nvm. It will leak less than a normal water glass can hold.

[rogbmw]

I am now ready to do the job. I bought new heater core (BEHR) and it came with all the needed O-rings inside the package One question still remains:
Do I have to drain some of the coolant from the system before I begin?

Edit: Nvm. It will leak less than a normal water glass can hold.

You will have to drain the system - at least from the Aux Water Pumps. You will need to disconnect the water hoses at the firewall, so you will have water leaking out from there. Also, it is a good idea when you disconnect the water lines from the firewall, to disconnect them first from the aux water pump, and blow air through them thus pushing most if not all of the coolant out of the core and associated pipes resulting in less change of spilling water inside the car.

NOTE: Another thing to check - after you get the new core in, put water in the system and pressure test it BEFORE putting the front of the heater box cover back on. Why do I suggest this ..... because I got a BAD brand new heater core from BMW (stuff happens!), and it leaked as soon as the system was pressurized, and of course, after I had put everything back together. So - everything had to come back apart and a second NEW heater core installed. The paint in the garage is still blistered from my comments uttered when I found out the new core was bad!