I installed the system today! Pictures are coming. It took me about 5 hours doing it solo. Everything lined up great. The hardest part was hanging the compressor. It was a tight squeeze through the bottom of the engine bay, but I figured it out.![]()
I installed the system today! Pictures are coming. It took me about 5 hours doing it solo. Everything lined up great. The hardest part was hanging the compressor. It was a tight squeeze through the bottom of the engine bay, but I figured it out.![]()
OK, let's wrap this up.
When I installed this '97 system into my '92, I read the FSM installation directions a few times (linked above). It may be helpful to Google image search various engine bays shots for reference, too. Installing it is easier if you break it down into four sub-systems to install and tie together. Given that my AC electronics were still in place, I didn't have to worry about it until last to make sure everything worked.
Those four sub systems make it easier to tackle and install. They are: the evaporator assembly (behind the glove box), the condensor and drier assembly, the compressor, and the high and low lines that run along the passenger side of the engine bay. I am going to try to descrive what I did in each of those systems, in the order I did it based off the FSM instructions.
The Evaporator
Probably the most daunting of the install. I wasn't quite sure how this was going to play out because it is the least accessible part of the AC. In the posts above, I describe prepping the evaporator assembly and installing new o rings on it. I read a few posts on other websites and when all was said and done, it wasn't so hard!
There are key steps to getting it out, but first begin by removing the firewall grommets the tubes coming off the evaporator protect. Grab them with a pair of needle nose pliers and pull them away from the firewall from the engine bay side. Put them aside, you will be re-installing them later.
Next, remove the glovebox. There are four screws here. Two attach the glovebox to a strip of stamped metal, the other two remove that strip. If you don't remove the strip, you won't get the evaporator in or out. I had to remove my old evaporator assembly first.
There are two 10mm nuts that hold the evaporator box to the car. Remove those. Pull out the drain hose on the bottom of the box. It drains the condensation out a port in the floor. After that you will see a band on each side of the box. They have little mason jar-like latches on them, don't bother messing with the latches.
These bands merely act like loose stop-gaps to keep the air moving to the rest of the ventilation system. They don't really seal anything. Slide the one on the right farther to the right and it should expose the end of the port on the box. Now pull the box away from the firewall off it's mounting studs. The box should drop down. If it doesn't, try pushing it to the right to remove the left port from the vent system.
One the box is free there are two wires clipped to the box. Use some needle nose pliers to grab them and remove them from the box. Take note or take a picture of which wire clips where.
The box is free!
Take the box/evap assy outside. There are a number of spring clips that hold the two side of the box together. Use a flat screwdriver to pry them off. Be careful, they may shoot away. I launched one about 12 feet away,out the garage. Put your other hand over the clips as you pry them off to prevent that from happening to you.
This is where it gets interesting. Carefully separate the two halves of the box. The evaporator in inside, encased in an insulating styrofoam shell. GENTLY separate the styrofoam shell. If it breaks or cracks, don't worry, you can use some duct tape to patch it up.
Remove the evaporator assembly. There will be some interesting grunge, dead bugs, leaves and other debris in here.
Now, comparing the two evap assys I had (92 and 97), I couldn't discern any difference between them. You could re-ring your old one, clean it, maybe replace the evaporator valve if you are so inclined, and reinstall it.
Take not of the little plastic piece that locates the tubes that come out the box and through the firewall. There is also a small passage for the capillary tube. Clean everything thoroughly and gently. It will be pretty dirty.
Reassemble the box and install it back into it's location behind the glovebox. Install the two 10mm nuts loosely to hold the box in place. I used a flat screwdriver to slide the bands over the ports in box. The ports have little ribs that show you where the bands should stop. Reconnect the two wire clips to the box and reinstall the drain hose. Replace the stamped strip that hold the glovebox, then the glovebox itself. Go around to the engine bay and replace the firewall grommets.
That's it!
The Condenser/Drier Assy
You can do this step next or the compressor assy, it's up to you.
I replaced the drier before installing this assembly. It's easy to do at this point and most pros will recommend you do it anyway. It's $15 at the most brand new.
Something I should have mentioned earlier; there are a lot of soft metals in the AC system (aluminum, copper, brass), they are easy to bend so use some tactful force when you work on these parts. A lot of the parts also have REALLY sharp edges, like the fins on the evaporator and condenser, so wear cloth gloves to save your hands. Some of the working spaces are tight and simply brushing your hands on them may cut them.
Onto the drier! Loosen the fittings on either side of the drier. Every AC fitting has two sides. USE A WRENCH ON BOTH SIDE AT THE SAME TIME WHEN LOOSENING OR TIGHTENING THESE. You can bend, crush, tear the tubing if you don't. The tube may bend a little in during this, but you can easily bend them back CAREFULLY. If the tube collapses, it's no good and you need to replace it.
Remove the two 10mm bolts that attach the drier to the condenser. Finish removing the fittings you loosened previously.
The new drier might come with new o rings. If not remove the old o rings and lay it next to your assortment to find the right one.
If you aren't sure, lay them side by side. The new ring should be a little snug, needing a little force to slide it on. If it drops on, it may be too big. If the o ring twists while sliding it on, it may be too small. Don't let the o ring twist up while sliding it on. Always lube the new rings with AC compressor oil or Nylog before reinstalling.
Bolt the new drier to the condensor with the two 10mm bolts. Reinstall the fitting on both sides of the drier. No need to go Hulk-smash tight on these fittings! Refer to the FSM link for torque settings to get an idea of how much to tighten them.
OK! The assembly is ready to install at this point. It may be a good time to straighten any bent fins in the condenser at this point. Inspect both sides and gently straighten any flattened fins with a pick tool or small, flat electronics screwdriver.
Lift up the front of the car, like you would to do the front brakes or something, use jackstands.
You will have to remove the air diverter first. It's 6 bolts, IIRC. It's the black plastic piece between the front bumper and the radiator. Place it aside and work the condensor/drier assy up from the bottom. the top of the dryer will be on the passenger side, facing the front of the car, just under the upper radiator support. There are four mounting tabs on the condensor that correspond to mounts in front of the radiator. On the driver side, there is one stud in place. This is helpful to line up the condenser. Use 3 10mm blots (about 16mm long) to attach the condensor at the other three points. The upper mount on the passenger side is a royal bitch. Removing the bumper tilting the radiator will help. It will take some patience. The other three are pretty easy. Good to wear your gloves while doing this part!
From underneath, look up into the mall space between the condensor and the radiator. Make sure the gap is consistent and the two aren't touching! They will rub through one another pretty quickly if they are.
With the condenser/drier in place you can now move to the next sub assembly...
The Compressor Assembly
Completing this portion took more out of me than the others. The weight of the compressor and the flexible lines attached to it make it a little awkward to maneuver into the engine bay. I have power steering, so the hydraulic lines made it a tighter fit. Because of that, I had to install it from the bottom.
If you have power steering, you want to slacken the tension on the belt and remove it. You will need a new belt that is compatible with your configuration. The old belt will also interfer with the installation of the compressor.
Next, there is a cast iron bracket that is needed to be installed to the side of the block. I would recommend prepping a few things first. Check to see if the holes for the bolts that attach the bracket need to be chased. You're dealing with iron here, so sometimes it can fill with rust and debris. Also, check the holes ON the bracket that the compressor mounts to. Test fit the bracket to the compressor. Start by installing the bracket with the four bolts. Don't forget to install the fifth, longer bolt that runs perpendicular.
Here is the r134a and r12 compressors side by side. Not much difference except the tags on he back that list the refrigerant it is designed for.
I had to remove one of the flexible lines to get the compressor up onto the bracket to install it. I was re-ringing these anyways, so no big deal. At this point you may want to drain the oil in the compressor and pour in new compressor oil compatible with r134a.
I don't recall the exact amount, but it is only a few ounces. Any autoparts store will carry the oil.
Install the compressor to the bracket with the four, longer bolts. Reinstall the flex line mentioned above, if applicable.
The hardest part here is from "T-rexing" - big body, useless arms. Working from underneath, the blood drains out of your arms and you are left trying to handle the compressor which is about 10-12 pounds. They start 'rexing and you have to rest.
Connect the single electrical lead from the compressor to the connector found near the driver's side headlight. Zip tie the loose wire to the coolant hose it is near to prevent the compressor belt from catching it.
Install the new belt over the crank pulley, PS pump and compressor pulley and tension it.
Almost done!
Last edited by kung fu jesus; 06-10-2012 at 08:20 AM.
High/Low Lines
Time to install the high/low lines (h/l lines).
I had to remove the intake on my car to gain more room to install these. This is where some engine bay pics are handy to see how they run.
If you are installing a new pressure switch, this is the time to do it, before they are in the car.
Start at the firewall, test fit the line at the bottom of the two from the evaporator. Lay it in for now. Do the same with the upper line.
My camera died on me at this point. Look under the car and take note of where everything connects to. You won't be able to misconnect them if you take a minute and look at the connections.
Remove the washer bottle for more access to the connections at the firewall.
Install the lines at the firewall. Re ring and lube.
LOOSELY attach the h/l lines to the brackets that connect them to the engine bay along the passenger side. There are two brackets, each has a single 10 mm bolt.
Get underneath the car and look at the connections to be made. The H/L lines overlap each other at places, so study the bends in them to make sure they are oriented correctly. When you feel confident they are correct, connect the H/L lines to the compressor flex lines and the condenser assy.
Connect the bracket that bridges the flex lines off the radiator, at one of the fan mounting bolts (10mm).
Check the hard lines thoroughly and make sure they dont interfere with each other. they should tough one another nor the car except at the mounting points. You may have to bend them gently to get them to clear.
Tighten the brackets down, reinstall the washer bottle, check to see if your fuel lines are interfering with the H/L lines. Use zipties to create clearance.
At this point, you are done! You can lower the car and reinstall the intake and anything else you may have removed.
I have a lot of o rings left over. I didn't disassemble the compressor and a few of the lines. I am confident they will be alright. Save the extras, they look compatible with fuel injectors and other items on the car.
Last edited by kung fu jesus; 06-09-2012 at 08:38 PM.
Checking the results...
Fire up the car and turn on the AC. Your car's idle should jump up a bit. Turn off the AC and the car. Your compressor clutch won't engage because there isn't any pressure in the system. The pulley will turn, but the forward end of the compressor won't. Don't worry, this is normal. It does this to protect itself.
Remove the connector from the pressure switch on the H/L lines. Jumper the connections on the harness side with a piece of wire. Start the car again. Go to the engine bay and look at the end of the compressor. It should be turning now. If it isn't, check your connector again, check the jumper. If that isn't it, you will need to diagnose the relay.
If you don't have a gauge manifold set and vacuum pump, take it to a service shop and have them evacuate the system, check for sustained vacuum and refill with refrigerant. If you didn't add oil to the compressor, tell them. Also, tell them you updated the AC system from a newer model. Give them the year it is from so they know how much oil and refrigerant to add.
Good luck!
Success! Shop called back saying,"system is tight as a drum, blowing ice cubes.".![]()
Lets get temp gauge on that, I"m curious the temp differential
if I had one, sure. It feels colder than Tina's NB.
Cool! I just finished having a 1990 "de-converted" from R-134a back to R12. Apple shut down mac.com, so that URL is dead. The new URL is http://webpages.charter.net/a7037196/miata/90ACINST.pdf (or you can use archive.org and the old URL).
It won't be too much longer before R134a is the same price for R12. Good for you getting it done now than later.
Wow stumbled on this thread and it will help so much. I plan on keeping my old AC but it helps to have a written guide.
1990 Miata, she was red but now she is Spirit Green!
http://mazdaroadster.net/showthread....d-a-love-story <--- build thread!
Also check out the facebook page http://www.facebook.com/IHeartFlippyHeadlights !!! Its a facebook page dedicated to the awesomeness which is flippyheadlights! Not me, but the actual headlights! High time someone noticed how awesome these things are; check it out!
Charter shut down webpages, so that URL is dead. The new URL is https://www.dropbox.com/s/45si5ni8cl...CINST.pdf?dl=0
kung fu jesus (06-01-2020),MaRcOp01o (06-01-2020)