ST185 AC system overhaul with photos

Ok, so I stated that I was going to post a thread about overhauling my AC system. So I’m going to start. I have a lot of photos and narration to include. That said, I realized that I will have to do it in installments. It would be too lengthy if done all at once. My apologies for that, and I ask for patience. I am fortunate to have a good friend who happens to be a professional auto mechanic. It is his shop, equipment and especially guidance that made it possible for me to complete this project and with success! So not long after I finally got Night Fury shipped to Texas from Maryland, I discovered that the AC was not working. Yes, it was March, but here in Central Texas we can and do get warm days throughout the year. I brought my ailing black dragon to Noah’s shop and asked him to check it out. He said a lot of technical things related to Air Conditioning, but then boiled it down to this,”you’re going to have to replace everything that you can, and thoroughly flush and clean the rest, if you want a decent chance of it working and continuing to work well“. I trust his professional judgement and had his assistance on a similar project previously. I ordered the new Denso parts from Rock Auto. I purchased AC system Flush(1/2 gallon can), AC oil(PAG 46), a multi-pack of the green R134 O-rings, and new pressure fittings with caps and schrader valves, all from O’Reilly Auto Parts. 3 weeks later(now April) I finally have an entire weekend off and just as important, Noah has time to help and an open bay in his shop! E3C835AC-6ACF-4871-8376-7859B47DC3D6.jpeg Hood up and ready to get started! C6DD786B-EC91-4409-88A6-34CBBFD018BB.jpegMy first task, after Noah evacuated the system, was to disconnect the fittings that connect the evaporator core and expansion valve to the engine bay components. There is precious little room to accomplish this between the firewall and the back of the engine. I had to carefully move the wireloom containing the engine wiring harness out of the way, so I could see whatI was doing. Backer wrenches are very important in order to avoid damaging the aluminum fittings.7644AD9B-2B82-49B2-B08C-5FCCE52EC0BF.jpeg
Here is another view, with the fittings now loose.
The next step was to remove the evaporator core housing from behind the glovebox. I took several reference photos to be sure that I could replace all of the fasteners and wires to the correct places. There are four nuts and four bolts according to my factory service manual. After I removed all of the wiring, I removed the fasteners saving a conveniently placed one for last, so that I could support the unit as it came loose. Then with a little help from Noah, who guided the fittings through the rubber firewall grommet, I carefully removed it , keeping it tipped back to avoid spilling oil onto the floorboard.4E419B61-88D6-4B22-9380-CA7482A52050.jpegE914C79B-9CAC-4AF5-92EC-B78122783A3B.jpeg461122D4-2A2D-44C5-B041-63A6379706B4.jpeg
housing removed, oil leaking out of the fittings that shows signs of metal particles in it indicating compressor failure.
That‘s all for this installment of the project. Save the thread and check back for more soon. Please leave any comments, questions or criticisms of my posting methods. Still learning and will listen to input.


Active member
This is very timely because I want to get the AC back into my car next winter. Were you able to remove the core housing without removing the entire dashboard?
Now back to the project.
I have removed the evaporator core housing, now I need to remove the old core and expansion valve, then install the new one in the housing.10DF0CDC-176B-4ECB-ABCE-DE6FA62665C2.jpeg
view of firewall where the housing was removed. Some of the fastening points can be seen, as well as the holes in the wall for the connections.
before splitting open the housing, I took care to cut the foam sealing gasket at the seams. The gasket was in very good condition.8792A57D-9ABD-49D9-8951-61BF8F244A0F.jpeg
reference photo noting location of sensors on the evap core.5A3EA31E-DBE4-4C5F-AD9F-0BE4DEF3FCA5.jpeghousing with old core removed showing how much crap can accumulate and steal efficiency.
view of core with more crap and telltale oil on the expansion valve tubing.67DAC082-3243-4611-927A-B66DEE583B3E.jpeg
this one shows why there was a leak allowing oil outside of the system in this location. When this system was previously converted to R134, All of the system O-rings should‘ve been replaced with the green ones designed for R134. You can seen the old black ones that failed and were leaking at the expansion valve.F185DD41-FA7A-4CC4-817C-9862A01496AE.jpeg6D63BE4A-BFD7-41CE-BCC3-8CA6A6DC6361.jpegF64DB605-2640-4D73-8417-5B53FD8B922B.jpeg
comparing new Denso components to old to insure correct fitment. Note new green o-rings supplied with the expansion valve.

to be continued
Just a bit more now. Want to finish posting the evap core refit. C8C83873-914D-4DF9-BDE5-C4A2240EA393.jpeg
A thin coating of pag46 oil must be applied to every O-ring prior to reassembly of parts.
View of the assembled evap core and expansion valve and cleaned and flushed tubing(more on flushing reused parts later, very important).
Opposite side view showing sensors inserted into the new Denso core at the same spot as the old one.
976D4EFC-5A4C-4B6B-BEC8-FC61D86711E7.jpegC9A33BAC-050F-4256-8AA9-4506E6223BBF.jpegViews of reassembled housing with new parts. Note corks to plug tubing and keep out dust, moisture and contaminants, until ready to b reinstalled on firewall. Night Fury looks on in anticipation and approval! That’s all for now folks. More when I can. Please reply with comments, questions, critique. Thanks!
Its past Time to do another installment. Here goes!
Having completed the Evap core, I moved to the front of the car and removed the dryer, condenser and hard line. After removing the shielding and hood latch, horns etcetera,here is the veiw. B535DE6E-CBDB-4955-94F0-E8C0A7260A38.jpeg
next I removed the bolts holding up the Tranny oil cooler, and fan motor.
some PB Blaster was used to encourage some bolts loose, as evidenced by wet spots.
Next I removed the hard line attached to the top of the receiver/dryer. Look at the ugly stuff that came out! The dark colored stuff is more evidence of metal in the system likely due to compressor failure.FE5F8110-A261-4DDA-847A-3EBCFD6E9568.jpegB79B39CD-53AC-4D51-9725-D959CAC14E91.jpeg
The dryer was being replaced, but I reused the line, so I cleaned it thoroughly with the flush. Next I removed the condenser, very carefully, since this part was to be reused and is not easily sourced. I failed to get photos of the removal process, but recall that it was not too difficult. Once out I had to do my best to thoroughly flush the condenser. I relied on friend and mentor Noah, who provided this awesome device to use with the flush. CA607CCC-5E25-4DEF-988A-96D03CB22DCC.jpeg
you fill the container with the flush and connect it to an air compressor. Then I placed it over an oil drain pan and blasted flush into one end of the condenser 417E6360-1D35-4721-A3E3-95247FDEE519.jpeg
This is a messy job, I had to used eye, and skin protection. After this photo was taken, i switched to heavy duty nitrile gloves. The process of cleaning the condenser, took awhile. I repeatedly filled it with flush, picked it up and sloshed it around, back and fort, tilted left right, shook it. Then drained it out. Then repeat. Blast it from the opposite side, shake, tilt, tip, drain, repeat. Repeat again. You get the idea. BE80C8C3-0210-403A-873F-7F543F360C36.jpegNope, still not clean, repeat, repeat. Finally, I was satisfied that I had done the best I could. Stood it up over the drain pan to drip, while moving onto the next steps. The can of flush was one gallon. I used about half of it on the condenser. Another quart or so on the various lines.
That‘s all for now. Hope to continue soon!


I’ve never had any of the HVAC out of the car before. I found it pretty interesting that the evap housing just slides in. Makes sense though. Not all cars had A/C from the factory, but it was available as a dealer installed kit. I always assumed the whole dash came out to install it, which would have been crazy expensive to install for an accessory.
I’ve never had any of the HVAC out of the car before. I found it pretty interesting that the evap housing just slides in. Makes sense though. Not all cars had A/C from the factory, but it was available as a dealer installed kit. I always assumed the whole dash came out to install it, which would have been crazy expensive to install for an accessory.
I know this is true. When I shopped for my compressor, there were two different part numbers for the car, one said “factory installed ac”and the other,”dealer installed ac”.
I will post the final installment of this project soon. I had intended to do so over the holiday weekend, but different automotive project took most of it up. Fuel tank replacement in the jewel of my fleet!5749EC66-6EB6-429B-8CBB-B593B7E8EEBB.jpeg