Air Conditioner: what would you do?

[Erik the Awful]

Yeah, this is the "scary" thing I've been dreading. Working with refrigerant under pressure. Perhaps it's not that bad? I've just have always been wary about working with it as an amateur, since a bad move would seem to have consequences, unlike working a wrench on a bolt. Ha. Perhaps time to swallow the fear and research it more.

It's fairly benign. I'd be more worried about working on a 60 psi fuel line, and I do that pretty regularly.

If you want to tackle air conditioning yourself you'll need a decent set of R134a gauges, a decent vacuum pump, the correct adapter to plug the vacuum pump to your gauges, and the correct adapter to plug a can of refrigerant into your gauges. You're looking at about $150 in tools if you buy a single-stage vacuum pump.

 

[PlayingWithTBI]

vacuum pump, the correct adapter to plug the vacuum pump to your gauges,

Hell, I made my own out of a compressor from an old freezer and a fitting I had laying around. Wired in a switch and soldered the fitting on the suction side. The compressor has oil in it so I have to keep it upright but, it works just fine.

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[Crazydavez28]

I've replaced a couple condensers (rocks hit them) and the new ones from rockauto already had the orifice tube installed. IIRC The rear air condenser has nothing in the condenser and has seperate ones for the front and rear lines. In my case I had to pull the orifice tube out and put it in the correct spot. This is where mistakes can be made.

It could also be overcharged with a faulty high pressure cutout....the gauges will be your guide, as well as a duct thermometer.

 

[Bone Shaker]

Hi everyone. First time poster here.

I'm trying to resurrect air conditioning that hasn't worked for some years in a 1997 C2500 Suburban -- single AC system (no rear air). I thought the system just needed to be recharged, but it has proven an exercise in "chase the problem." Took it in for a recharge with die, the compressor started short-cycling again within a few days. Fine. The shop found the presumed leak and filled again for free.

However: more short-cycling. Well, there was a leak at the compressor, and the compressor itself was showing resistance (which made sense -- you could feel it in the steering wheel whenever it kicked in). Fine. New compressor, not too bad for price. Got to short cycling yet again. Had another leak at an o-ring the shop replaced and recharged for free.

More short cycling! This time, evidence of leakage at the condenser. Ok, it's starting to get more expensive than I planned, but fine. Replace the condenser.

Well, that brings us to the present situation. Now everything seems to be working mechanically. For the first time ever, the compressor kicks in and runs all the time, no cycling at all. That's kind of what I wished it would've done in the past, because the air never got extremely cold, even right after the (ultimately failed) recharges. It felt like it was cycling off too fast to get really cold. But I thought it was supposed to cycle some at least. And now, the air is not getting cold at all. It may be very, very slightly cooler than plain vent, but it's close enough that I'm wondering if I'm just imagining a difference. In any case, that's obviously not right. It's strange and seems to point to something -- but what?

So what would you look at next? From all that I've read, this could indicate a plugged orifice tube or a problem with the evaporator. But as I'm amateur, I don't know if one or the other is more likely, or if it's something different altogether. Again, why is the compressor on all the time?

If you're talking evaporator, it sounds like a person would have to pull down the dash, which gets you either into a seriously long project for an amateur, or very high price job, even at the reasonable shade-tree mechanic rate. For a 23-year-old truck. Now, the good of that is I could have the blend doors themselves replaced at the same time, as the air flow is weak and I'm leaking air to the defrost vent no matter the setting. Yes, I've done the remove-the-blower-and-clean-out-the-junk trick. And the blend door actuator itself is working (replaced it recently myself). But if you're talking like a $1500 bill, maybe it's time to plow that amount into a somewhat newer Suburban, maybe a GMT800. But of course then you inherit a whole new set of problems.

I'd love just to get the AC blowing ice cold, and make my own "blend door" by stuffing a towel over the defrost vent when not needed.

So what would you do? Try the orifice tube replacement? Replace something else? Bite the bullet and have the full dash removal project done? Invest in a newer truck and relegate the '97 to 3-season duty? It's such a great family hauler, hate to lose it for summer trips.

Try everything before you do the evaporator core. It’s a big job(like all weekend for me). I just got my a c straightened out and I am so glad
O b w if you go into the heater box evaporator box be sure to replace the heater core also. I would only trust genuine a c delco parts. I don’t ever plan to do this again. Good luck and holler if I can help

 

[Bloke]

So what happened in the end with your ac issues?

I took me better part of 2 years and 2k to get my AC not only cold but not leaking. Replaced ac hoses, drier, compressor, orrfice tube. Not sure if i changed condenser or its the original lol. After all that it was cold but after 3-4 months it would leak. I was like WTF, I would recharge every 3-4 months until I had enough money for whatever came my way.

Narrowed down to the evap core, So last March/April? i had my mechanic tackle this job, The connection between the drier and evap was buggered and hence my leak. Take the dash off change the evap and heater core while your their mate. Hindsight should have changed the motors to them doors cause, 1 went out this year.

Got those parts in, needed a better dash cause mine was all jacked up with cracks and holes. Used at a yard for 280. Used a rattle can grey from autozone and stuck with that color for the rest of the interior trim.

The dash and parts and whatever else i did cost me like 2300 in the end. The ac switch to the controler over cooked this year so i had to get a pig tail and new switch. Hey its cold and it doesnt leak. So the dash looked so good i didnt stop there and did another carpet change, dynamat and then leather seats. I have always taken care of this truck and it all started 2016/2017 with a paint job and the snowball started there and its almost done. lol

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[Armalite15]

Just a suggestion here, not a tech but have been in auto parts for over 40 years so far. When doing an A/C job never replace a compressor by itself. At a minimum do the compressor, orfice tube / expansion valve and the filter dryer. Several times a year I'll have a shop order a compressor and get the oh it's just the clutch that failed routine. Then the new compressor get trashed because they didn't change out the other components which were in fact contaminated but they thought they could get by without them. And all the large A/C supplies won't pay a labor claim if you don't flush the A/C system as well as replace the parts listed above. And really on a vehicle over 10 years old a condenser is really cheap insurance. Just my.02

 

[Bigred81]

I had similar issues. I have a 99 burb with rear air though. My most costly mistake was not doing it all at once with quality parts the first time Long story but I replaced orifice tube 3 times compressor twice and took me 3 SUMMERS TO GET IT WORKING CORRECTLY. Because I didn’t take my time, buy quality parts and I had some electrical stuff. The hvac box under the dash took me 12 hours in my drive way. I wished I had just purchased a new hvac box with all new servos on it. I didn’t take my time (driveway in 100 degree temps in Utah) and my dash has cracked in a few spots now when before it was flawless. The pressure, why high in the system sounds worse than it is. I was thinking the same thing you were. Also make sure you put the orifice tube in the correct direction. I believe it flows one way And take your time. This website and YouTube saved my butt and could have saved me money. I’m in my AC system over $1,500 including recharging and vacuuming 5 or 6 times and I did all the labor other than vacuuming and charging. Had I done it right the first time it would have been more than 1/3 that cost and 1/3 the time.

 

[96-2D-Hoe]

Used a rattle can grey from autozone and stuck with that color for the rest of the interior trim.

I'm curious how that turned out and has held up?
How close was it to the original color?

 

[Schurkey]

everything seems to be working mechanically. For the first time ever, the compressor kicks in and runs all the time, no cycling at all.

I guess that rules-out a plugged orifice tube.

I thought it was supposed to cycle some at least. And now, the air is not getting cold at all.

The compressor should cycle, but that depends on ambient temperature. If it's hot enough outside, it's not going to cycle.

No cycling, no cooling probably means the compressor valve(s) have failed. It's not actually pumping. Connect a set of gauges, see what the pressures are.

the air flow is weak and I'm leaking air to the defrost vent no matter the setting...

...I'd love just to get the AC blowing ice cold, and make my own "blend door" by stuffing a towel over the defrost vent when not needed.

The blend door doesn't divert air to the defroster. The blend door controls air temperature by reheating some portion of the cooled, dehumidified air.

There's always some air at the defroster vent. That's intentional.

So what would you do? .

Connect gauges. See what the pressures are.

Put a friggin' inline filter in the low-pressure hose leading to the compressor if the system has to be opened-up again.

 

[DanJ]

Thanks, everyone, for the insightful posts. This is helping me think through the possibilities. No updates yet, but hope to have news by the end of the week.

This is why I roll the windows down and go faster.

Yes, when as a boy I asked my grandfather where the air conditioning was in his early '60s C10, he said "roll down the window when we're at 55." But I'd like to take the family south of I-80 in the summers without broiling.

The blend door doesn't divert air to the defroster. The blend door controls air temperature by reheating some portion of the cooled, dehumidified air.

There's always some air at the defroster vent. That's intentional.

Ah yes, I should have said "mode doors." Does seem more air is escaping to the defroster vent than should be, especially relative to the other weak vents, but maybe that's all in spec and the fan itself is just poor. Sure sounds like it's spinning up a storm, but I know the blower motor replacement would be easy, so maybe it's worth it just to throw a new one in and see if it improves.