87 924S heater core

[SolReaver]

OK folks, I am doing the heater core on my 87 924S. The Dash is out. With the factory AC there is no other way. Since I do not want to disconnect the AC condenser I am thinking removing the Core by sliding it to the right will not work. My best guess is that sliding the box to the right is the way to go, as you can see it is pretty tight. Any advice or suggestions would be appreciated. If anyone has done this job...Please chime in. At this point it is getting to be a real pain. The best directions so far have been from 924.org.

[SolReaver]

picture is worth a few hundred words at least..

[SolReaver]

Sorry no pictures. The heater box is now loose after I took out the controls and disconnected the four bolts that you take off from the engine compartment. I had to also remove the fan. It looks like I can pull it straight back after disconnecting the coolant lines to the core. I intend to pull the core out with the housing and then clean and rebuild the housing with a new heater core. The hoses will be taken out the front. I will drain the coolant, attach the new hoses and heater valve, and then route them into the passenger compartment.

This is a MAJOR job. My car is totally torn apart at this point.

[John_AZ]

Hi Sol,
Your comment on getting a new heater core rather than test and reuse the original makes sense for the amount of work involved. Pelican can get the OEM # 171 819 031 D on special order for about $140. There is a Audi/VW/Fox+++ interchange but I cannot find it for our cars-924, 924S and early 944.
Meyle makes an interchange for $54:
http://www.***************/search/product.aspx?sid=v23zie455kcnzf45y332go55&makeid=800019@Porsche&modelid=1263316@924%20S&year=1987&cid=24@AC%20%26%20Heat%20-%20Climate%20Control&gid=6864@Heater%20Core

GL
John_AZ

[SolReaver]

I have the interchange. It was cheap. I just hope it fits.

[SolReaver]

Hey! the cheap interchange fits! BTW John, after THIS amount of work...any sane person will replace the core. For the price it is a very prudent investment. Although I hate to admit it, to do the job right and have a nice smelling car with proper HVAC I had to go this far. The HC removal from the side cannot be done without removing the AC condenser unit and housing. Also, at 22years old the foam seals on the internal flaps of the heater box are not surprisingly..rotted.

It has taken me a while to get back to posting because I had some technical difficulties with the camera and the job has become a bit more than I anticipated. While I had the heater box out, I decided to rebuild it as the foam seals were gone and there was a lot of debris and dirt mixed with crusty antifreeze. (yick) I hosed out the box as best as I could before beginning the rebuild. I will spare you all the pictures of junk and nastiness. The old heater core leaks. What a surprise!

Here is the Box out of the car:


remove the clips and open her up:



Disassembled:



Like I said...The foam seals were all rotten:



the necessary supplies:



One of the flaps needed to have it's spot welds drilled out and had to be carefully pried apart.


Finally all the flaps are rebuilt:



Ready to go back together: Ok, to be honest I had this thing apart a few times getting the flaps to seal just right. Make them larger than you think they have to be and then cut them down to size after you test fit them in the unit and bolt it together.




All together now...Wasn't that fun?

[SolReaver]

Almost forgot.. put the Heater core in the heater box and instal the cover:

[John_AZ]

Sol,
Your pictures really showed the work involved to get at a leaky heater core. In this picture, the dry rotted seals and flaps show the necessary work to to the job right. I also see the black crud in the vents you mentioned. Nice work on rebuilding the flaps.



What a huge amount of hours to invest in a necessary repair!

Thanks for the update.
John_AZ

[SolReaver]

Okey dokey, putting it back in the car now. Here is where it goes.

Still have the dash to do and the wires need to be straightened out. The rear shield frame is painted and drying. Still looking for a glass guy 2 install it.

[SolReaver]

OK, It has taken me a while to get back to it. The Airbox with core is in and fitted.
Note that the controls are attached and the flaps tested nicely. I hooked up a vac pump to the AC actuator and that flap tests good as well.

The hoses to the back of the heater core are glued in with blue glue and the clamps are loosely in place. If you place the clamps just right they can be approached with a long screwdriver or nutdriver with an extension for the top clamp and a short screwdriver or nutdriver fort he lower clamp. I would attach Pictures, but they really don't help. Under the hood The blower motor was installed on the top and the blower cover fit in place. Thanks to John AZ I have a good idea of where the HC coolant lines go and am now seeing if I can get it all attached. There is not much room to work and I am spending a lot of time in the dark area around the sensor block. Things are not all lining up and I am getting a feeling that the HC hose to the valve is the wrong one. I am taking this opportunity to finally straighten out this hard to get to region between the engine and the fire wall. What fun.

[SolReaver]

OK, The job was completed about a week later. I will see if I have the pics to add.

The HC hoses and controls were a PITA as I remember and then assembling the dash back into the car involved a lot of fitting and fussing. Work the dash in slowly all around and loosely bolt it in. then let it sit in place and "relax" for a while before tightening it down.

[AKCJ]

OK - that's a lot of work. A few questions.

1. Did you have to disconnect the A/C lines? I assume so.
2. In post #9 above the pictures shows the car taken apart way more than I would have expected to replace a heater core. Did you have it torn down for something else? Or is that all for just the HC?

As old as my car (heater core) is I keep expecting it to start leaking at any time so I'll probably be doing this some day.

Thanks for posting your project.

[944 Ecology]

Very nice description of the job, and nicely done!

[onZedge]

Was it really necessary to remove the blower? Clearance issues? ...or was it just like any other repair on these cars: "Remove five things to gain access to the thing you actually need to get at".

[SolReaver]

AK: this is what you have to do to remove the core WITHOUT disconnecting the AC. My AC worked champion before the project and still blows Ice cold. Not disconnecting the AC is doing it the "hard way", but, I find that overall the problems involved in taking down a factory AC system that has never leaked from day one and that still has a full charge of R12 outweigh the benefits of a quick fix.

THe new HC is the bees knees! Cranking heat and frosty cold on demand with nice tight plumbing!

Besides...the Dash needed to be repaired, the flaps were all rotted, and there was mold and icky stuff that needed to be cleaned out.

OnZedge: Oh yea, the fan came out, the heater box would not have come through with the fan attached. I rebuilt the fan while it was out. No biggie.

[jjeffries]

Bumping this excellent thread because I'm about to perform this task ... the reason I took out my dash in the first place.

I don't want to open-up my a/c lines, which Sol's approach manages to avoid. I will also emulate him by replacing the foam in the flaps and generally santizing things.

If there are any other pointers for this job from the wiser folks on this forum, please feel free to chime in.

Thanks, John

[88Silver924S]

Where does one get the replacement foam? Is there a brand name, thickness, etc specification? Also details on the sticky sealing strips, etc would be welcome. Good luck with your project.

[jjeffries]

Ha! I was wondering the same about the foam for the flaps. I’m guessing it’s 5/16 - 3/8 sheet. My local hardware store doesn’t have it; will check a Staples or craft store next.

For the foam strips, I use hardware store 3/8 wide, 5/16 thick self-stick ... it works well. I bought a few different widths to have on hand, it’s inexpensive.

I don’t know Sol (yet!) but PM’d him last night; hopefully he jumps in to school us. I ordered a heater core this afternoon.

John

[curtisr]

Originally Posted by 88Silver924S

Where does one get the replacement foam? Is there a brand name, thickness, etc specification? Also details on the sticky sealing strips, etc would be welcome. Good luck with your project.

Choose your weapon. Or, amazon to the rescue?

[jjeffries]

Curtis, that is a dizzying selection! John