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2,198 Posts
Discussion Starter #1
Ok, the 8V is out and 16V is apart so the engine compartment is empty.
I figured I might as well replace the heater core, its probably the orginal one since this car is a 91 and I don't think the recall included that year.
So just so I know its new , its replacement time.
My dash is in excellent shape, basically perfect and I don't want to mess it up, so I'm gonna take it slow, and I plan on doing this without removing the dash.

I've searched the archives checked the Bentley, and no I have never done this before.
What I've found is:
Thanks to GranTurismoInjection for his post dated 09/16/05, he posted a link to a PDF file of the actual repair procedure from VW.
The Bentley and the VW process as well as some other posts are big on telling you how to do things without giving specifics.
So my plan is to post pictures and info from my heater core replacement in order to help others, tips and info that are not mentioned in other post.
OK my center console and knee bars are out. simple enough
Day 1 - for example, info says take out the lower floor vent section, but what you don't get is that there are 3 screws 2 on the left side and 1 on the right which is hidden way back on the right side, and took a while to find. And the 2 screws in the front of this section do NOT have to be removed.
pic showing 2 screws in front section that do not have to be removed

pic showing 2 screws holes left side,

pic showing securing tab on right side, rear of section,

and where this screw/tab connects

OK, center A/C vents, info says remove it, great, and all that I've read says pry them out with a small screwdriver. I don't like prying on new plastic, especially 15 year old brittle stuff, so I found the easiset way was insert small finger left hand in bottom left corner, right hand small finger top right corner, and pull out gently. And don't try to tilt the vents up to reach the screws in the top of the center A/C vent frame and remove it as a unit.
pic of how I removed vent without prying, ok I'm holding the camera with my right hand but you get the idea.

Center A/C vent frame - remove the 2 screws under the top edge but do not pry on the frame to get it out and risk damage to the dash. Remove the 2 screws on the front cover of the heater box and pull it towards you.
Reach you left hand behind the bottom edge and gently pull outward, this will push the center A/C vent frame out at the top enough to get your hand behind the frame and begin working it out.
pic - pull front cover out gently

pic - get your hand behind frame and work it out slowly

OK , I got things I have to do, tomorrow , another episode -

2,198 Posts
Discussion Starter #4
Re: (jamaicula)

Update time, with pics.
I removed the heater box first , and if I ever do another one I'll just remove the dash and take the entire heater/AC fan box out as a unit, and then separate it on the workbench.Those darn clips, be as careful as you like but you're gonna break some plastic tabs off the box itself as some are a ***** to get to.
Now that I got both boxes out, I have to say if your gonna take out the AC box, I don't see how it can be done without removing the dash.
I removed my AC box without removing the dash, but the only way I did was to cut off the evap lines in the engine bay @ the firewall.
I'm deleting AC anyway, so no biggie. theres just not enought room to tilt the AC box back far enough to angle it out from under the dash.
I have a pic below that shows where the AC box was hitting the dash.
Ok so I'm looking for a Non AC fan box but in the meantime, I need to clean things up redo some doors and seals in the heater box.
Check out the pics below for progress.
(thanks to paddy2bsure for his info he posted)
Day 2

AC / Heat control panel
The knobs do just pull straight off without any problems.
To remove the panel just grab the middle of the panel right along the center rib on the left side where the fan speed knob was and after that side pops up, do the same on the other end.
pic showing the back side - the big round plug has all the terminals marked on both the panel and the plug itself.

pic- removing front cover of the heater box I just turned it to this angle and pulled down slowly to remove.

pic- showing 3 screws to remove heat /AC panel
check that old school cassette deck

pic showing heater box after front cover was removed, you can see the heater door that once was covered in foam.

there is a vent behind the radio that goes from the heater box to the center defrost vents that needs to be removed so that the gasket on top can be replaced. There are 2 screws holding it in, one on each side
pic showing screw on right side of vent.

pic showing securing bolt for AC box behind glove box

pic showing where AC box hits dash bracket

So I'm deleting AC anyway I just cut the evap lines @ the exp.valve and this allowed me to tilt AC box back enough to clear dash and remove

Ok I removed the heater box by separating it from the AC box (darn clips) and then removed the AC box.
Now there are 3 things you are going to need to repair the doors and the gaskets
Goo gone to remove/clean whats left of the old adhesive/foam

Go to Wal-Mart and in the hobby/crafts section get some "Foamies", these are adhesive backed sheets of foam that even come in assorted colors (I almost got red ) I found this idea by using the search button, imagine that.
pic of a sheet of "Foamies, I bought 3 sheets

Next head to Home Depot / Lowes / hardware store for some of this, basically just adhesive backed foam insulation used for windows, etc.

I used the Goo Gone to clean all the crap off the top of the center defrost vent that I removed.

And then made a new gasket out of the insulation roll, much better.

and side view

I read in some of the old info I found using the search button that some people in cold climates have used screws to keep the doors open instead of fixing their heaters.I'm not sure about this screw shown in the picture but its screwed into an actual boss made into the housing, but it keeps the door from closing all the way.
Anyway as you can see in the pic all foam from both doors is gone, and check out that screw in the bottom of the pic, any ideas.

Ok next is the little door that controls the defrost / floor vents thats inside the heater box, you can see whats left is just the adhesive back of what once was foam covered.

cleaned with Goo Gone and then replaced with new foam insulation strip

the front cover that was previously removed

backside showing old adhesive, whats left of foam

pic after cleaned with Goo Gone

next I'll be recovering the doors with the "Foamies,
before I go. pic showing that boss that those screws are screwed into, anyone have any insight on these screws.
Boss on top right

and the screw thats screwed into it

next , covering the doors


5,680 Posts
Re: (tomorrowtomorrow)

I'd like to see the pictures of the foam covered doors, as I have to do this eventually. What adhesive are you using? It has to stand up to some decent heat.

2,198 Posts
Discussion Starter #8
Re: (vwgtipowr)

Quote, originally posted by vwgtipowr »
I'd like to see the pictures of the foam covered doors, as I have to do this eventually. What adhesive are you using? It has to stand up to some decent heat.

I'll do the foam covered doors tomorrow and post pics and info then.
the foam sheet is adhesive backed, peel and stick, we'll see how well it sticks to the doors and go from there http://****************.com/smile/emthup.gif

2,198 Posts
Discussion Starter #9
Re: (16ValveInside)

Step 3
Covering the doors
I cleaned the metal doors with Carb cleaner, it works better on metal than the Goo Gone, use the Goo Gone on the plastic stuff.
Do not use carb cleaner on plastic,

pic showing metal doors after cleaned with carb cleaner

Also cleaned out both pieces of the heater box with soap and water, might want to cover the openings of the vacuum diaphrams with vacuum caps first to keep water out of them.
pics showing cleaned out heater box

Measuring out the self adhesive foam before cutting, remember to allow for enough foam to go around the edge. You want to cover front , edge, and back with one piece.
setup pic prior to cutting

After cutting and foam stuck to one side.
pic showing adhesive back pulled away enough to cover one side in foam

pic showing reverse side after front has been covered in foam

Wrap it around the edge and cover the back. This stuff sticks to itself really good, so be sure to press it together so that the sides touch through the holes. I did a test piece and tried to remove it just to check and it was really tough getting it off.
pic showing one door completed

pic showing edge,

pic showing other side

pic showing finished door installed

Pics showing covering the other door

Pic showing half of other door complete

pic showing door edge

pics - covering rest of door

pic showing other completed door

pic showing both doors re-installed

check out how door on right side seals up against the edge of housing

Previously I had covered this mixing flap with the adhesive backed foam insulation strips, but I removed that insulation and covered it with the "Foamie" stuff because I wanted the EDGE of the flap covered so it will seal better.
Pic of flap previously covered

pic of flap installed with no foam showing gap between the edge and the housing.

I used what was left of the original flap foam as a template, and cut a piece to cover it.
pic showing original from flap used as template

pic showing flap covered in foam, much better

pic showing flap / doors completed and in the box

Ok, next episode is going to cover sealing the box back together and what I'm going to do about the couple of broken tabs for the securing clips.
And I have a Non AC fan box on the way so that should be interesting cleaning that up and attaching to the heater box.


10,257 Posts
Wow you're the DYI climate control guru lol. Great thread! You should suggest this to be added to the FAQ.

2,471 Posts
Re: Heater Core Time (16ValveInside)

This is the most detailed wright up I have ever seen http://****************.com/smile/emthup.gif

5,680 Posts
Re: Heater Core Time (dubalub)

Quote, originally posted by dubalub »
This is the most detailed wright up I have ever seen http://****************.com/smile/emthup.gif

Yes, very nice job, and great detail as well.
Is that foamies stuff thick enough to make a good seal?
The doors in my heater box don't seem to seal that well from what i remember, and I am trying to prolong taking it apart again as long as I can.

1,150 Posts
Re: (evilrobot0)

Wow that sounds like a pain in the farkin ass job.
And my mechanics first thought when I said I have a slow invisible coolant leak was my heater core?
And the leak has gotten to the point where I need to refill the resevoir every couple of hours.
Kinda pissed. Running out of options, ideas, defenitlely $!

2,267 Posts
Re: (lemooresgliguy)

NNEEEED PICS! hehe. If it is at all possible to get these pics emailed to me in a .zip file or posted back up on this thread?!
This is an amazing write-up!
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