syc0path

I have an '88 Trans Am w/ the 305. The air conditioning stopped working a few years ago. I actually have some of the old freon, so I was able to recharge it. But it lasted less than a year. Before I recharge it again, I'd like to figure out where the leak is and fix it if possible.

Also, I'm not opposed to upgrading the system to a modern setup, but from what I gather, that's an expensive and time-consuming job. Any1 have a parts list, costs, write-up, etc?

scooter

iTrader: (11)

You can use what you have and put in 134a, but you have to clean the old oil out of the system first, which would require opening the system. At the very least you will need a new dryer once you open it.
Leaks? Most likely at one of the joints the O ring has dried out, or the compressor is leaking and needs a re-seal. You really should get some dye in there and try to find the leak with that, or just start replacing stuff

gearhead141

Unless you feel confident about working on your a/c system, I say leave it to a professional. In order to find a leak, the system has to be serviced. Do you own a vacuum pump? That is a must have to evacuate the system. Then you need a set of gauges to monitor the vacuum. The tools needed will likely amount to what you will pay someone who does this for a living. If you want to do some of the work yourself, and the system is empty, then check the O-rings and Schrader valves. Those are the most likely causes of leaks. If your car still has the original black O-rings, they should be swapped out for the new green type. These are things you can do that the shop would charge you for. That way, when you bring the car in, you can just say, leak check it and service the system. Oh, and yes, a new dryer is a must.

CorvairGeek

Most likely source is the front seal of the R4 compressor. Dealing with the R4 is rough for a DIY, as GM/Delphi hasn't made them for years and the replacements (even if they say AC Delco) don't have a good reputation.

Reid Fleming

iTrader: (2)

I wish I could say there is an easy solution for this (and there may be). But there may not be. From my experience, the most common spot for leaks are the schrader valves themselves.

Having said that, I've replaced the valves, replaced the hose, run dye in the system, used the UV light and glasses, run my electronic leak detector that beeps and gives a number depending on the size of the leak.....Nothing found. Pulled the evaporator out, expecting to see black oil and green dye if a leak was there. It was clean as a whistle. That leaves me with the condenser up front.

For a Michigan car, I wouldn't be afraid to switch to R-134a. You're far enough north that the performance differences should be minor. If you lived in Arizona, Florida, or anywhere in the deep south where humidity is an issue. I would recommend fixing the leak and sticking with R-12.

sofakingdom

iTrader: (1)

It's wherever you see the oil.

Look at your underhood noise blanket: if you see a streak of oil on it right above the compressor, it's the compressor seal.

Look at all the hose ends: factory hose becomes permeable and allows the system contents to pass into the hose material, and it then comes out the ends of the hose.

Look at the service valves: the valves themselves frequently leak and then rely on the cap O-ring to seal, which isn't what they're there for... those O-rings are only for keeping out dirt and water. If the valve leaks, the O-ring doesn't stand a chance of keeping the Freon (or oil) in.

Look at every fitting where a line bolts to something: there are 2 such places at the condenser, 1 at the evaporator, 1 at the accumulator, and 1 where the accum bolts to the evap. Plus of course the 2 seal things where the line assy bolts to the comp.

Finally, look closely at the comp itself: the comp itself is a cast aluminum body, and the entire outside of it is a big round sheet-metal band that slides over it and seals with 2 YUUUUUJJJJE O-rings. A terrible system, GUARANTEED to fail if the outside piece is distorted from, say, improper tightening technique at some point in its life. Also, the "stop" that limits how far it pushes onto the pump body, is a little metal tab with 2 spot welds, and those can crack and cause a leak.

I would NOT recommend keeping R-12. While the unfortunate truth is that newer refrigerants are functionally inferior, the difficulty and expense of obtaining 12 over the long term make it a poor choice for other reasons besides purely technical ones.

Best thing to do is, EFFF a bunch of "Find the leeeek". Gut and renew THE ENTIRE THING and be done with it. Much like an automatic transmission: you don't tear it down, replace ONE clutch or band or gasket or something, and put it back together otherwise untouched; you do THE WHOLE THING all at once. Either DO or DO NOT: there is no "fix".

Replace the accum, comp, orifice tube, and all rubber line sections (use "barrier hose" which is basically polyethylene pipe with a rubber coating); use 2 of the actual AC hose clamps, the big fat wide ones, on each hose end, NOT the little weenie cheeeeep heater hose ones hanging on cards at AZ or wherever; use the Frod red-orange orifice tube, NOT the original GM white one; flush the hard components that you will re-use (evap, metal line sections, and cond) with lacquer thinner to remove ALL TRACES of old oil, debris, and the waxy substance that builds up as the original oil deteriorates; pour about 3 oz of the mid-weight PAG oil into the suction port of your new comp, and about 3 more into the new accum (you want the oil that's in the 75-100 viscosity range, not the 45 or the 150 kind of stuff); evacuate to within 1" of Hg of deep-space vacuum, leave the vac pump on it for at least a half-hour, and verify that it loses no more than 1" after the pump is removed and the caps installed, and you wait another 2 hours; and fill the system with 134.

And of course, make sure that your cooling system, ESPECIALLY the fan and all the shrouds, are in PERFECT operating condition. Remember, the AC doesn't "generate cold"; what it REALLY does is to MOVE HEAT; and the function of transferring heat from the refrigerant to the ambient via the condenser, is EVERY BIT AS IMPORTANT as transferring the heat from the passenger cabin to the refrigerant in the evap. Both heat transfers must be optimally effective for the system as a whole to be optimally effective.

JamesC

iTrader: (5)

This post brought back a nightmare that lasted for several summers. I'm uncertain about how much time and money I spent at various shops trying to trace the leak. The general consensus was that the leak was untraceable. Baloney. Finally, at a little shop owned and operated by an old GM mechanic the issue/oil was discovered on the back of the condenser. New condenser, end of problem.

JamesC

Bow_Tied

iTrader: (1)

Great thread and info.

syc0path

Absolutely, definitely some good info here. I think I know what one of my winter projects is going to be!

syc0path

Well I said this was gonna be a winter project... I just didn't say which winter! I'm gonna take sofakingdom's advice and replace all the parts. I started looking at Summit Racing... does any1 make a kit or have a collection of the necessary parts?

I'm gonna replace the condenser too. IME, that's 1 of the most likely parts to fail, since it's up at the front/bottom of the car. My TA doesn't really have any rust, but it did see 4-5 winters.

I'll try to do the mechanical work myself, but I think I'll take it to a shop to charge the system. I do have access to the tools, but my success rate on other vehicles is about 50/50. Is dryer another term for the evaporator?

Bob88GTA

iTrader: (2)

https://www.rockauto.com/en/catalog/pontiac,1988,firebird,5.0l+305cid+v8,1251469,heat+&+air+conditioning,a/c+compressor+&+component+kit,17507

https://www.rockauto.com/en/catalog/pontiac,1988,firebird,5.0l+305cid+v8,1251469,heat+&+air+conditioning,a/c+refrigerant+hose,6900

Yes, Dryer is a accumulator
The condenser is the coils

rt66er

iTrader: (2)

This is what I bought and installed, then had it charged by a pro...
https://www.originalair.com/88-92-ca...-r134a-stage-3

i88aGT

You will need to decide if you want r12 or r134. This affects your choice of compressor, condenser, and oil. I would do 134 if I did it again, for simplicity.
And you will need probably everything from the kit in that post ^ from original air. You may not need the evap and liquid line.
Pricing everything out you may be able to get things slightly cheaper, but I did this and did not feel it was worth it. The original air kit is a bit pricey, but last summer I noticed if you put the condenser in a separate cart and then the stage 1 kit in another cart the total will be cheaper.... If you do r134, that parallel flow condenser, pretty much exclusive to original air now, will greatly improve performance, I've read. You may want to pick up a different orifice tube and belt than what's in that kit.

If you choose to part things out as I did, here's my experience with what I got this summer:
1. Dryer/receiver (stock) from AZ - Good
2. Orifice Tube from NAPA - Good
3. High pressure line switch (stock, wasnt working) NAPA - Good
4. Custom hoses from local hydraulic shop - Great
5. Sanden bracket kit (vintage air brand) Summit - Bad, had to replace carraige bolts with my own because they were too long and would rub belt, and find my own spacers to make it actually fit, and lock nuts took a funky tool size
6. Oring AC Fittings 331009 (vintage air brand) summit - Bad, missing oring size to fit from accumulator to suction hose
7. Sanden 508 compressor (tuffstuff brand) summitt - Bad, product delayed and not as described and since removed from their cat.
8. Condenser (stock, spectra) AZ - Meh, doesn't leak but I did not like the sloppy paint, and there was some damage to the fins, blew it out with air in case their was debris inside and there was some.
9. Refrigerant oil NAPA - Good
10. Miscellaneous schrader valve cores and core removal tool NAPA - Good
11. 99.5" serpentine belt (continental, for my sanden 508 conversion) - Good, was a bit squeaky for couple weeks.
12. Butt splices with heatshrink already on them NAPA - Good

blacksunshine'91

iTrader: (10)

It says saves weight, but how much? Was it actually noticable (like the difference between a stock starter and a mini-starter, or stock water pump and aluminum water pump)?

syc0path

That's pretty much what I was looking for... how do u like it? Are the parts well-built, does it put out good, cold air, etc?

It's like u'r reading my mind... I thought the kit was a bit expensive and thought about piecing it together, but then I thought it probably wouldn't be that much cheaper. Should I get the red Ford orifice tube that sofakingdom recommended? Would u recommend the 99.5" serpentine belt that u used instead of what's in the kit?

BTW, why does the serpentine belt have to changed? Is the compressor pulley a different size than the stock AC compressor?

Great info, guys... thanx!

rt66er

iTrader: (2)

I had a few glitches with the kit. The instructions left out a couple of things that were fairly obvious but I felt unsure about. I think they expect you have some experience with A/C systems. If I had it to do over, I would try the red Ford orifice; the white one that comes with the kit is leaving some cooling off the table, me thinks. I had to buy a slightly bigger belt; the one they included worked, but the tensioner was not in the "preferred" range. Plus, I have a AIR delete pulley, which might have made a difference. The only other thing is the top line bracket on the condenser has two sheet metal screws holding the tubes to the bracket and they are too long. I had to take each one out and shorten or they would hit the radiator.

i88aGT

I believe sofakingdom has the best advice for r134 parts, go by his recommendations because he clearly has experience to back it up.
Cant say for certain what belt will work on yours. probably in the range of 99.5"-100.5" if stock. Look up how the coding works for belt sizes so you can inform your auto part store worker, because he/she might tell you it cannot be searched by size.
The belt needs to be longer because the bracket kit lifts the compressor up and to the side from stock.
Final piece of advice: expect the unexpected. There's always something that needs to be tweaked a bit, just as rt66er said about the condensor sheet metal screws. Or how instructions leave out that you may need to undo the trans cooler line so you can shift the radiator enough to wrestle out the old condenser (btw u can use cardboard between the rad and condenser to protect the fins during install). But if you're lucky like me you'll end up with a nice leaf collection from back there when youre done. Oh ya, and you'll have working AC that you can enjoy. When it's done you'll be happy you did it whenever you drive the car.

rt66er

iTrader: (2)

FWIW, I did speak with Classic's tech and he was very interested to hear my observations. Said that he would personally check out the condenser situation, so it's possible they may have corrected this problem.

syc0path

I'll also be happy that I won't have to listen to my wife complain that it's too hot out to drive a car w/ no AC

I'm ready to order... any1 have a discount code for Original Air? I tried searching online but didn't find any that were still valid. It's $52 for tax and $100 for shipping, so the final cost is over $900

Also, how about a part# for the Ford orifice tube, or maybe a RockAuto link? I tried searching RockAuto, but I didn't have any luck.

J.C. Denton

iTrader: (1)

Look at the 96 Ford Crown Victoria at RockAuto, that's what you need. I also swapped to R134 with the white orifice first and the red/orange orifice improved cooling noticeable.

i88aGT

Is that for the stage 1 and condenser in separate carts? because you may not need the evap and liquid line if you clean them. and u can switch the schrader core for $1 or so and the tool is less than $10 if you need it. there are schraders in the liquid line and drier.

syc0path

I got the Stage 3 kit, which comes w/ everything, rather than trying to piece it together or reuse 30yr old parts.

So far the installation has been pretty straightforward, but I'm having a problem installing the evaporator. The instructions say to remove the old gasket from the old evaporator and put it on the new evap. The problem is that the old evap has a flat front edge, whereas the new part is slightly recessed at the top and bottom. As a result, there are gaps (big enough to stick my thumb in) at the top and bottom of the evap case. This means that the AC will be sucking in hot air from the engine compartment, which will severely reduce cooling performance. It also means that water and debris will enter the evap case, and it will be a great place for mice to nest during the winter. Any thoughts on how to address this? I tried calling Classic Auto Air and just ended up on hold until they kicked me off

Note gap where bottom tube exit case

syc0path

I just noticed that in some places in the directions, it says the kit is for years 89-92, and in some places it say 88-92. I have an '88. Are there any differences between '88 and '89 that might explain the issues I'm having? In the directions, there is an info sheet about how to cut and re-crimp the hose. But I shouldn't have to do that if it's a pre-fit kit!

scooter

iTrader: (11)

Foam isn't going to stop mice, ever. Even sheet metal doesn't stop mice, so forget about that.

I am guessing you're concerned about the gap on the RH side of the picture? If so, then your worry is misplaced. Once you put the lid on you're good, you only need concern about the gap in the front, where to tub is in the lower part of the box and around the tubes. If you have larger gaps there, get some foam from a hardware store and cut to fit, or buy some window foam and stuff it in the hole. Also, you need to make sure there are no gaps at the top of bottom of the evaporator, so air cant get past without going through the cores. Some more foam will fix that, if necessary.
Functionally, 82-92 should all be pretty close, so I don't think you have a year application issue, just generic-ish parts to replace factory specific ones.

syc0path

Yeah, the gaps at the top and bottom is exactly what I'm worried about. I can add more foam, but it should be closed-cell and be about the same density as the original foam. I'm thinking something like copper water pipe insulation like this at Home Depot.

The kit states that the hoses are pre-fit. The piece they sent me isn't even close, and does not match the illustration of the parts in the kit. I figure I need about 15-18", and the piece they sent is 62"!

scooter

iTrader: (11)

There isn't a lot of room between the stock evaporator and the bottom, and the factory only used a thin piece of foam glued inside the case. I wouldn't worry about putting foam in the bottom as the top, since you don't want the foam to hold water in the case. I would just go with the type with the adhesive strip for use around windows rather than the pipe stuff since that is more rigid, you want it to conform as much as possible