jschiller

I have my heater box out of the car as a result of tracking down some wiring problems. I have tested the three vacuum actuators and found the comb flap actuator to have a slight leak so I will be replacing the diaphragm on that one. Before the electrical issues, the A/C was woefully warm and I want to solve that before I put it all back together, including new expansion valves, receiver, o-rings throught.

So my question is, is there anything useful to be gotten from opening up the heater box, enough to offset the risk of doing something stupid and breaking the box getting it open. I can only think of cleaning the heater core and evaporator or blower resistor as offering a reason to open it up. From what I can see, there is none of the crud buildup like here:
https://rennlist.com/forums/928-foru...-cleaning.html
I think I can hose that out.
So, should I open it up?

Schocki

Absolutely, open it up and inspect and clean the inside. Most evaporators will look like this and are close to leak due to corrosion. If in doubt replace.

It would be also a good idea to replace the o-rings for the heat exchanger, replace the expansion valve, drier and all o-rings you have access to.

Christopher Zach

How much of the interior did you have to take out to get it removed?

jschiller

The Pod, dash and center console had to come out, so essentially you have to gut the whole thing.

davek9

Yep remove it, I'll add replace the "O" rings on the coolant pipes for the Heater core too and inspect the pipes for corrosion, also soak both core and evap in a good cleaner to remove any dirt/mold in the fins.
I ran both through my ultrasonic and replace all the flaking foam w/ new using heavy duty headliner adhesive.

dr bob

Replace ALL the actuator diaphragms while you have it apart.

The diverter door that's actuated by the little setting motor, plus the other diverters in the box all have seals on them that get crispy and fail. There are some interesting weatherstrip options you can use on those. The fitment is a compromise between sealing and too much friction. GregB shared some tips here a while back. Search will be handy.

jschiller

Ok, I'm convinced. I'm diving in.

"Keep on fixin' until it's broken"

Schocki

If you need pictures or advice, just ask here. I just did this last winter and converted my 92 GTS HVAC Box to a 94 unit with pollen filter die to a evaporator leak.
I took a lot of pictures....

The Forgotten On

How did you do that? Did you take the back of the back and attach your original 92 front or do some modifications of your own?

I've always been interested in doing this.

Schocki

I got a complete used unit from Roger. It fits with only very minor mods (the resistor unit for the fan).

dr bob

I think Gary Knox shared details of how he fitted a filter section in the duct between the fan and the evaporator. I was cleaning the Shark vacuum last week and feasted my eyes on the foam dust filter that fits under the cyclone canister. With a very slight bit of trimming and a wire support it would be a drop-in to fit just downstream of the connecting boot. High flow, low restriction, dust removal, readily available, minimal effort to fab and install. Pretty much presses all the right buttons.

mkhargrove

I think it's time well spent to spray some coil cleaner on it while you're at it. I think it's about $6 per can at Home Depot. Super easy.

jschiller

AARRRRgh, I knew I forgot something when I was there today. Thanks for the reminder!

Wisconsin Joe

"If it ain't broke, you're not trying"

jschiller

^Amen, brother.