Stuck on heater core replacement

[bbig119]

I managed to get to the heater core quickly, but am having problems removing it. The new one came with pipes attached, and I'm hoping the pipes aren't the problem, and that by removing the core seperately from the pipes, I'll save alot of time and effort.

However, after getting the front pipe dislodged, I'm having problems removing specifically the pipe that's closest to the front of the car(firewall). It won't budge, and it seems there isn't much wiggle room in the compartment that the heater core actually sits in.

Any tips/tricks or advice on how I should procede?

[bbig119]

RANT RANT RANT!!!!

Got old core out, and put the new one in...BUT....

I used the old pipes, and they seat properly, but the bracket that holds the two pipes that attach at the left side of the core isn't fitting the new heater core properly.

It seems that a plastic tab just below where the pipes mount is thicker on the new heater core, and the old bracket from the old pipes has a protrusion such that it hits the tab before seating fully so that the pipes can be tightened.

What is the purpose in changing the tab and bracket on the pipes when they are otherwise the same?

To that end, I presume I have three options. 1) sell the car. 2) try to alter the old bracket to fit the new heater core by shaving/grinding it. I have a dremel, but doing this with the pipes installed might be a pain, not to mention that the heater core is installed which makes that task even more risky and difficult. 3) install the new pipes that came with the new heater core, and everything should be happy-- I think.

If I opt to install the new pipes, I haven't seen much in the way of write-ups on this. How difficult will it be, given that I have most of the interior already apart to follow through with the installing the new pipes? Do I need new gaskets or anything where the pipes enter the engine bay and connect to rubber coolant hoses?

Thanks....so much for a trival 5 hour job.

[saconnect]

They should just pull right through the firewall to the inside with little work...heck you probibly already worked them loose anyway moving them around so much. I'm assuming that your new pipes have the firewall gasket thingie already on them like mine did, and you can just leave the old pipes connected, pull it out a little, then pull the pipes through the firewall...also saves a mess on the inside. Keep at it, and you'll figure it out, just try not to scratch anything since paint is very thin in this area.

[bbig119]

They should just pull right through the firewall to the inside with little work...heck you probibly already worked them loose anyway moving them around so much. I'm assuming that your new pipes have the firewall gasket thingie already on them like mine did, and you can just leave the old pipes connected, pull it out a little, then pull the pipes through the firewall...also saves a mess on the inside. Keep at it, and you'll figure it out, just try not to scratch anything since paint is very thin in this area.


Thanks... I'm leaning towards replacing the pipes as well. Do you know if I have to remove the dash to do this? Or is this pretty much a game of try to wiggle it through to the engine bay blind?

[George M]

Pictures help a lot when you get stuck. There are a few tricks to changing the heater core on these cars that makes the job go much easier. Inside the engine bay right where the three pipes protrude the firewall there is a single clamp held by a bolt that keeps the piping in place when connecting the hoses inside the engine compartment. You want to remove this clamp for fishing new metal piping which I am not convinced even needs to be done.
The trickiest connection is aluminum most driver side pipe to the core. Many spoil this connection which is a single bolt by pulling on the flange. One must rotate this flange not pull on it. When you get it apart you can bend the finger that goes behind the core to readjust for just the right amount of pre-load. The best trick for getting it back together is to use a long screwdriver and not your fingers to rotate this flange back into place.
Anybody who needs help on here should own an inexpensive camera and post pictures. Many on here know every bolt on these cars and pictures make the difference.
Good Luck,
George
P.S. the dash does not have to come out to change the piping however the piping likely does not need to be changed.

[bbig119]

Here are some pictures of the stuck clamp. I have more pictures for documenting the whole process, but nothing better to show where I'm stuck yet. When I get the heater core back out I'll take a picture comparing the thickness of the two tabs.

http://imageigloo.com/images/6240stuck-clamp.jpg

http://imageigloo.com/images/6709stuck-clamp2.jpg

The pictures don't show the tab that extends out from the left of the heater core just below the pipes by the clamp that won't slide down into position. After thinking for hours it was the pipes themselves that was causing it to be stuck we eventually determined that the tab on the new core is about twice as thick inbetween the pipes as the old one.

[bbig119]

Heater core out, old and new compared-- look at tab. There is a notch for the clamp to close on, and I'm unsure why I was unable to get it to do so in the car. In any event, old pipes are coming out, and new ones will be in. Hopefully this doesn't take too long.

http://imageigloo.com/images/9929tab-compared.jpg

[Eric Clark]

They should just pull right through the firewall to the inside with little work...heck you probibly already worked them loose anyway moving them around so much. I'm assuming that your new pipes have the firewall gasket thingie already on them like mine did, and you can just leave the old pipes connected, pull it out a little, then pull the pipes through the firewall...also saves a mess on the inside. Keep at it, and you'll figure it out, just try not to scratch anything since paint is very thin in this area.

You clearly have no clue how to do this repair. JT540i and I spent several house just messing around with the damn pipes. They are extreamly hard to get through.

I would do everything possible before messing around with new pipes.

[ryan roopnarine]

i would bet that new pipes would make no difference in that latch closing down fully. the clasp is a "bitch" that requires that the pipes be 100% in, it really isn't like putting a heater hose over a nipple. anybody that has a 1/91 or newer e34 and has done a heater core can attest to that clamp being a PITA to get back on. if you have new pipes, by all means, go ahead and change them out while everything is apart, as you've hit an impass anyways.

[tim s]

the heater box has a cover that is removable where the pipes come through.
it was not easy, but do able. make sure you replace the o-rings if you decide to use the old pipes. my heater core was not the problem, it only needed o-rings, but i had it apart & i already had the core so in it went.
here is my pics.
http://www.tntcomp.com/tim%20s/heatercore.htm
tim s.

[bbig119]

Got the heater core in and car functionally finally after another day or problems/issues-- this time with coolant flush and change to BMW blue.

To keep along story short, I and two other people tried their damnedest to get the aluminum bracket for the pair of pipes on the left(driver side) of the heater coreto lock in place, but I suppose we just couldn't wiggle/apply enough pressure to get them fully seated to allow the bracket to clear the the elevated portion of the tab on the heater core(see above) and lock the pipes in place. I ended up using a dremel to put an angle on it and that got it close enough that we were able to get bolt it in. Changing the pipes had absolutely no positive effect on the problems I had except taking a long time in twisted contorted position to get old ones out and new ones in through the firewall.

Yesterday during the coolant flush(even though the system is "self bleeding") I was running into over heating issues, so I decided to use the old funnel on the expansion tank to aid the bleeding. It spewed like a volcano several times throwing DI water or coolant all over the engine bay which in turn got into the wells by the ignition coils, in turn causing the car to misfire-- which made further bleeding difficult. After several unsuccessful attempt at drying the coils we realized that a bunch of coolant was actually in the well of the spark plug and when the coils were put on it must have pushed it up enough to short the connection to the plug. I ended up sucking up the coolant/water with paper towel wrapped on a long screw driver.

Car seems to run fine how. Microfilter changed(not as bad a job as I thought, but definitely more of a pain in the ass than something like it should be). Resistor pack changed, and appears to have solved the blower problems, but I haven't run AC too much yet. Heater core changed, and blowing hot air(which gets VERY hot at high rpm when on fully hot-- kinda makes sense). This morning the expansion tank was empty, so I topped it off. I guess I'll have to do that a couple times.

I have a bunch of pictures from the job(heater core stuff), so if anyone wants to see them or could use a few pointers I'll be happy to help.

In the end...definitely a pain in the ass job that I hope I never ever have to do again. That said-- I think I saved at least $1000, so even though I killed a weekend on it, and the better part of a monday with the coolant flushing problems, I came out on top.

Thanks to everyone who helped posted procedures, gave some advise on previous threads, or helped me with my problems this time around-- I couldn't have done this without the forum.

[saconnect]

You clearly have no clue how to do this repair. JT540i and I spent several house just messing around with the damn pipes. They are extreamly hard to get through.

I would do everything possible before messing around with new pipes.

I do appologize sincerly if I've mislead you in any way, I was just tryin to assist...I have done four of these without a hitch, and three of them I've put on the pipes that came with the heater core, and I've never run into this problem. :( I'm getting ready to do my 94 soon, so I'll probibly run into it there...

[Eric Clark]

The indy I use said the heater core is his second least favorite repair on the E34. The first being something that is behind the heater core but I forget what it is. To get to it the heater core and its entire housing has to be removed. I think I read some where that shogun said the record for a heater core replacement is 4 hours. I'd like to meet this guy because mine took 12 hours but next time I will not remove the damn pipes so I can get it done in one day.