83na944

I plan to replace the hoses from the heater core. I know I have to remove the dash, etc.

Do I have to disconnect and remove the evaporator to access the hose clamps on the heater core? Is the evaporator above or below the heater core?

TIA.

SoCal Driver

Think it's to the lower right side. Blows into the air box where the heater core is.

This is the early A/C system:



This is the early heater system:

83na944

So the ac box is separate from the heater box. So I"ll just need to remove the heater box to access the hose clamps. I feel I need to replace the original hoses, they're 21 years old. Thanks.

SidViscous

Do a Search

You need to remove the entire AC Assembly.

Complete pain.

Granite 944

I've just about finished doing this job (put the center console back in tommorow). Sid won't like hearing this, but, you can change these hoses without touching ANY part of the AC system. But....you must completely remove the heater box (as shown in SoCal's diagram) with the core in it and the hoses still attached to it, in order to gain access to the hose clamps. Time consuming, but really not that hard. I did this to my '83 car. If you decide to do this job, I strongly reccomend you consider replacing, and doing a few other things along the way with it (while your in there stuff). I would suggest, removing the steering wheel lock/ignition switch from the column, with the upper switch cover (at the same time. I used a slide hammer to get it off shaft). It will make dashboard removal/install much easier. Replace the elect. switch in the ignition at this time ($7.00 from Paragon). Seriously consider replacing the heater core in the box ($65.00 from Paragon). Replace the heater valve, and the hose to the head from it. I replaced all the sponge foam rubber seals on the ducts around the box (cheap, from any hardware store, open cell sponge rubber foam weather seal). You should really check/clean all the grounds under the dash, check all the wire harnesses for taped up spots and scotch connectors, (lordy, what you might find under that tape!) . Check all the spade connectors on your aux. fuse box for corrosion/snug fit. These are some things you might think about “while your in there”. I'd be more than happy to bend your ear with more, if your interested! HTH

SidViscous

I'd love to see how you removed the Heater box, without removing the AC.

Granite 944

Sid, I wish I knew back then (when you were doing it), how all this works out! I may have been more help than a hinderance back then!


This is what it looks like with the heater box out.




A wider view of inside car.




In the middle of pic, where ya see the nasty looking foam seal, is where a independent duct ties the AC to the heater box (yes, I did replace all the foam seals with new). Just to the left of this foam, you see the openings in the firewall for the hoses to run thru. Its strange, I don't see the tie-up duct (2 pcs.) in the diagrams shown by SoCal.



You must remove the motor, and fastners from the cowling also.




Of course, the complete heater box (without the tieup ducts on it).

83na944

Damn. I don't which is worse: the horror story Sid posted on the older thread of the pictures Ken posted.

Great pictures, Ken. So I guess when you removed the dash and center console, you just moved the heater box back toward the rear of the car to remove it. The reason I want to replace these hoses is that they are the only hoses I haven't replaced within the last couple of years. That little "L" shaped hose from the head to the HCV blew a couple of months ago and I ended up replacing the clutch. I don't want a blown heater hose to ruin the new clutch.

Ken, please bend my ear with more info.

Granite 944

Make no mistake about it, Sid is right! this job is no fun! Its not really as hard as it is time consuming. So if this is a daily driver your doing this with, your going to have a lot of fun pushing thru this to get the car back on the road right away! (at least, if you do some or all of that "while I'm in there" list). I suggest you have a backup car for a while.

Yes, once all fastners are removed, the side vent ducts, and duct tie up to AC, the heater box will drop down a little, and then pulls straight out away from the firewall with the hoses still attached. Then you can easily replace the hoses, and/or replace the heater core (which I strongly would suggest, if you don't know the history of it).

When I did a pressure test on the cooling system, I found that the heater valve, and the hose to it leaking under about 8 lbs of pressure. I was changing out the oil cooler seals, and had just replaced the waterpump and such anyway, so I started this project too.

I changed the ignition swich, installed a pwr. antenna, went thru the wire bundles and fuse/relay boxes, looking for/finding/fixing misc. bad spots like crappy splices, loose and corroded spade connectors and ect. When I dropped the fuse and relay boxes, out of the way, and had great access to clean up the main fuse box grounding spade trees, and ground point on pass. side. Replaced all the foam duct seals, cleaned fan motor, and guard to accept new ribbon seal, cleaned all the grounds on the bell housing, and installed new heater valve and hose there. I've replaced all the instrument panel and console light bulbs, hooked-up a switch in console for pwr. ant., cleaned up and consolidated all the wiring for the stereo, which was a horrible mess! Alot of this above, you will want to do also?

It just takes time

Let me know if/when your starting the job, I'll try to put together a simple to follow, process to get the heater box out, and back together. Or you can contact me at granite944@hotmail.com.

Mike C.

Granite, best photos I've seen showing this arduous procedure. I do get a wiff of anti-freeze when the heater hasn't been used for a while and then turned on. If my core is leaking though, it must be a very small amount. My coolant level seems to hold steady... I will have to face facts eventually....

Granite 944

Originally posted by Schlicten [/i]


I would say that may suggest a very small leak. A lot of times, a heater core won't leak until after its hot. After the car is shut down, temp. goes up in the core, expands a little more, maybe then leaks out a little? One reason why a radiator shop that does a pressure test on your core will tell you its still not a sure thing that it won't leak because the test was done cold. Or, it could just be some anti-freeze smell coming in from the engine compartment from another leaky spot.


I don't know about this......my smeller isn't all that good anyway.....I'm a smoker, though I'd think the smell would dissapate fairly soon, unless the leak is pretty bad, and you'd know ya had a problem by then anyway. At least thats been my experience with past/non P cars.

83na944

Well, I hadn't considered replacing the heater core. I know the condition - it is the original. No leaks that I know of.

Anyway, Ken's suggestion to replace the core started me thinking about getting a modified core with nipples long enough to reach through the firewall so that the hoses clamps could be attached on the engine side. This would simplfy hose replacement in the future. I think I'll check with a radiator shop about this Tuesday. Does anyone know the exact dimensions of the heater core?

And another issue I've been pondering is relocating the HCV. The only real problem I see is getting bulk hoses with the correct inside diameter and a longer cable to operate the valve. Has anyone done this or considered it?

SidViscous

Ken.

That really doesn't look easier

Though something I would like to do eventually.

83na944

Sid's approach would be good if you plan to work on the AC. Like replace the expansion valve or flush the evaporator.

83na944

Schlicten,

But are the clamps on the engine side of the firewall?