AC Help Needed. AC experts appreciated (Page 2/2)
sjmaye AUG 16, 09:57 AM
I did the flushing of the system and changing of o-rings myself. I am confident that part was right. Still, I think I have a leak.

I got the dye in and enough freon that the compressor clutch is not cycling. It has been 14 years since I flushed and put this all together. I do not remember the connections points. I expect those are the weak points and most likely where a leak might show up. Can some remind me where to look for the connections? It sure would speed things along.
sjmaye AUG 20, 02:49 PM
I did my extended drive with the dye in the system and now finally got the car up in the air to look. The dye is yellow, but very faint. It was one of those one-shot deals. I am afraid there was too little dye and it got diluted making any leaks quite faint. Anyway the only real place I saw what I think it something is at the evaporator.

Here is a shot of the evaporator without UV light



Here is with the UV light. All the open cell foam seal where the evaporator mounts has a faint yellow look. I am not sure you can see it though.


That evaporator looks like a bugger to get out. Before I go digging into that I thought I might put more dye and freon in. Maybe it will better confirm where the leak is.

Ideas anyone?
steve308 AUG 20, 02:57 PM
Be sure to check the AC condenser and the lines that run under the car.
sjmaye AUG 20, 03:09 PM

quote
Originally posted by steve308:

Be sure to check the AC condenser and the lines that run under the car.


I must have driven it at least 30 miles. Maybe I need to drive it more.
Macarchie AUG 20, 05:50 PM

I rebuilt the AC in my '87 three years ago. There is a compressor control valve in the side of the compressor that needs to be changed to accommodate the pressure changes needed for 134a. It is an easy swap when you have the compressor out or the car is on a lift. When you break the system down, don't forget to remove and clean the orifice tube (and screen). This is the 10 inch tube that lays along the firewall from the base of the master cylinder to the accumulator. It is almost guaranteed that the orifice tube will have black gunk in it. It is also a good idea to replace the accumulator because undoubtedly, the desiccant may now longer be absorbing the moisture. New O-rings (especially the ones on the connections for the condenser in front of the radiator). Do not over-tighten the lines going into the accumulator - trust me when I tell you that the plastic nuts will break. Pour 4 ounces of PAG oil (I used PAG 100) into the accumulator and four ounces into the compressor before sealing it up and pulling the vacuum. After pulling a vacuum, the system will take 32 oz of R-134a and it should have 8 oz of PAG. Low pressure side should be between 22 psi and 29 psi / High side should be between 130 and 190. The AC lines pass through the joint (behind the driver) which allows the engine to be lowered without disconnecting the AC lines. There are O-rings at the joint that should also be replaced. Even though these cars are small, they have some long AC lines because the compressor is in the rear and the condenser is in the front. These cars are so small that it is easy to get them icy when the system is working properly.

Good Luck !

- Jimmy

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1987 Fiero coupe; Blue; 2.5L; 5-spd
1987 Firebird Formula; Blue; 5L; 5-spd

sjmaye AUG 20, 06:27 PM
Now granted it has been many years since I flushed, replaced the orifice tube and accumulator. I think I have used the AC a handful of times since then. Are you saying it needs to be totally redone, again?
Dennis LaGrua AUG 22, 09:01 PM

quote
Originally posted by sjmaye:

Now granted it has been many years since I flushed, replaced the orifice tube and accumulator. I think I have used the AC a handful of times since then. Are you saying it needs to be totally redone, again?



If the system has completely emptied, then you need to find the leak, fix it , replace the accumulator then evacuate and charge. If you used leak sealer then you will also most likely need to open up and flush the lines as a first step. Old leak sealer is really bad stuff and can kill your compressor but the newer high tech stuff like A/C Leak Freeze will not clog your system when opened. The best idea is to find the leak and repair it.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 08-22-2020).]

sjmaye AUG 23, 05:18 AM

quote
Originally posted by Dennis LaGrua:


If the system has completely emptied, then you need to find the leak, fix it , replace the accumulator then evacuate and charge. If you used leak sealer then you will also most likely need to open up and flush the lines as a first step. Old leak sealer is really bad stuff and can kill your compressor but the newer high tech stuff like A/C Leak Freeze will not clog your system when opened. The best idea is to find the leak and repair it.



I decided to put a little more freon and dye in in hopes if there is a leak it will show up better under UV light. This was about a week after I previously charged the system. Oddly, the pressure was about where I left it. No change I could see. Still, the pressure was low. I loaded another can of freon into it along with the dye. I am took it for a couple extended drives and will inspect.

Couple questions-

1- Does it matter how long I wait before inspecting? Over time will the dye lose its glow under UV?

2- During my latest drive I noticed the engine temp gauge was way below normal (under 100) after a very long drive. Turning the ignition key on and off showed the gauge move, so it was responding. I waited a few hours for it to cool down (assuming the gauge was wrong). With the AC off I turned the ignition key to the ON position and the radiator fan was running continuously. Can there be any relation to the work I am doing with the AC?