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Discussion Starter · #1 · (Edited)
Hello, there!

I'm replacing every major AC component (everything except hoses and tubes, which have been flushed; not willing to fight with old hardware) on my '97 Tracer and I almost have everything ready; however, I have some concerns:

I have already taken the evaporator assembly off (great writeup on this site) and I bought an UAC evaporator core, but it seems its tubes are too long; if I install the support bracket from the old one, it lays too high and the casing won't close; if I want to lower the tubes, I have to bend back the outlet one to a point where the angle might be too restrictive and the opening might be too far back anyway. Is it OK to install it without the support bracket or should I have the old evaporator's tubes welded to it?

EDIT: Had the tubes modified to fit.

I have some digital service information and it has been very useful, but it doesn't say how much PAG-46 oil to add to a bone-dry system. I have read a Third Gen has a maximum of 6.75 oz. opposed to the Second Gen's 8 oz. How should I distribute it?

Thank you so much for any input you can give me.
 

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from my experience with 3rd gen AC, i wouldn't sweat the PAG.
i add some if/when i open up the lines. you are a 3rd gen, so you could just stick with 6.75. i would split 3.5 into low side hose that runs into compressor and 3.25 into accumulator. not much other place you can put it, unless you can put into the evap core directly. there isn't anything moving there though? maybe put 1 oz there while reducing from other two spots? your accumulator feeds into the evap core direction anyhow? i would not sweat this.
since you are re-doing most everything, be sure to pull that vacuum, and with that much effort, i'd do a 24 hour pull at least to make sure no leak.PAG all your O-rings too during install. the switch at the accumulator has an o-ring too that could be easily overlooked - and i would screw that one tighter than it came off (mine was really easy to unscrew).
2 cents.
 

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Discussion Starter · #3 · (Edited)
Thanks for the info.

I can pour some oil into any part, as they're still out of the car. Would this be a fair distribution?

  • Evaporator core: 2 oz.
  • Accumulator/Dryer: 0.75 oz.
  • Compressor: 3 oz. (Service manual implies it's the minimum for a replacement)
  • Condenser core: 1 ounce.

Service manual says to pour 3 oz. in a new evaporator and 1 ounce in a new condenser, but I'd rather distribute it all around while still leaving most of it inside the compressor.

Thank you for the info about the schrader valves! I already bought the replacements for both service ports and got all new (green) o-rings for every connection, including the ports for the cycling switch and high-pressure transductor.

I don't know if I can make a 12-hour or a 24-hour vacuum pull, as I don't have a closed garage, so I'm basically working on my driveway; the noise would startle the neighbors :cry: I've read 45 minutes should be enough, but I also want to be sure to remove all the moisture. Would 4-5 hours do? What about doing it in stages? Although, I understand there might be a condensation issue with a partial vacuum left overnight.
 

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you pull the vacuum.. and let it set for 24 hours to make sure no drop or very very minor settling of the needle.
not pull vacuum for 24 hours straight.

yeah.. you have to lube it all, the O rings in all the couplers. the 97's still have 2 O-rings each connector tube, i think the 98's or later have 3 O-rings (from observation from pulling junkyard hoses and looking).
either work fine, just as long as have the right O-rings.

if service manual says to fill a certain way, i would suggest following that? your oil might distribute a certain way after startup.. so i think that should be followed. you might move an ounce, maybe half an ounce around if you will feel safer? but i think everything gets moved "into balance" after XXX cycles.

if you are in a hurry, you can just pull vac and see and pull and see. i do that a few times for like 20 to 30 minute intervals, make sure nothing leaks, even after is shake stuff around .. then i do an hour vac and let it go. if/once you find a leak, you gotta address it right away.
Leaving a partial vacuum is better than open air? i don't see how that can be bad. the more vacuum the more likely the moisture stays in gas form, so i dunno how "partial" can hurt your system at all. i've clean leaked fully out a few times. still on original compressor, condensor, evap core. only changed tubes and accumulator. but you might be much more moist where you live and i might just be really lucky.

2 cents.
 

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Discussion Starter · #5 · (Edited)
I see. I thought people were letting the vacuum pump work all night to boil out all excess moisture due to environment differences and precautions (living on a Mexican beach, I grew wary), but I can certainly make a 1-hour vacuum pull and let it sit for a day to check if it holds. Thanks! Also, every o-ring will be oiled before and during installation, for sure, and the dryer is going in last, to avoid it being in contact with air as much as possible.

Unfortunately, the service manual only specifies individual replacement procedures, not a complete system rebuild, so whenever it says how much oil should a part contain, it's in the context of replacing only that part in an already-operating system; por example, separately, it states 3 oz. for the evaporator, 1 ounce for the condenser, 2+ oz. for the accumulator/dryer (plus what the old one had) and a minimum of 3 oz. for the compressor (depending on what the old one had); that's 9+ oz. total if I followed each replacement procedure, which is inconsistent with the maximum capacity I've found for both Second- and Third-Gen cars. Of course, I understand everything will eventually even out through the system, but I wanted to avoid any part working dry for an unnecessary period of time, even if the only moving parts are inside the compressor; so, to make sure everything has some oil in it, I'll distribute it like I suggested.

Thank you, again, for your input.
 

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you would melt down a vac pump if you let it run all night. ideally you want to run it long enough to pull vac down to 500 micron and then let it sit in an area thats at least 70*F. that will boil off any moisture, then run the pump for a bit longer. you can pull a vac on it all day, but if its not 70*F you still wont get the moisture boiled... most ac machines dont pull to specific vac microns anymore, and its done by time. if its 70* out, I have always just ran it for about 10 min, then sit and watch gauge for a second to see if there are any large leaks, you will see them immediately... then i walk away for a bit, come back and run pump for another 10 min, and then charge. if it is too cold out, you can run the engine with hood closed until hot, and that will heat everything up.

distributing the oil is a good idea, just best to have the bulk of it on the output of the compressor side, so as that you dont get a huge gulp of oil stalling the compressor.
 

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Discussion Starter · #9 · (Edited)
Got everything together, pulled vacuum for an hour, disconnected the manifold (car's in the open), left it overnight, connected the manifold with the valves closed, pulled vacuum in the manifold, opened the system to the manifold and the needle on the low side went up to -5.

Turns out the low-side service port valve is toast and it seems it's a JRA valve, not a Schrader. I hope I'll find it soon; meanwhile, I pulled some vacuum and left the low-side connected to the manifold to avoid leaving the system open.

EDIT (no need to bump the thread): Service valves replaced, pulled vacuum in two one-and-a-half-hour stages, checked that the system held it overnight, recharged 28 oz. (794 g.) of R134a and now I'm a happy popsicle! I finally have A/C! I think this car had not had a functioning A/C system in over 15 years. It was worth the effort.
 

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crap i forgot to mention that. i replace the service ports every time i have the system evacuated. extremely over looked part, it wont show a leak because the machine is hooked to the leak source.
 

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Discussion Starter · #11 · (Edited)
The system is cold, but I have an issue, as I was expecting it to be a little colder with the new parts:

While running, pressure on the low-side is 45-50 psi and 110 psi on the high-side with a weather of 79°F and 80% humidity, max. AC, full-cold and blower fan in second speed.

I noticed my serpentine belt tensioner vibrates, so it's time for both a new tensioner and a new belt. Would this vibration cause these readings and somewhat-low alternator output?

As I don't have any equipment to evacuate the system to check for blockage or to change the compressor, I'm going to have to take it to a shop for further checkup.
 

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The tensioner will have at least some vibration no matter what. When it's really on the outs it will start to basically chatter - big fast vibration with very noticeable noise. The noise is really the distinguishing feature. You can find videos with audio of it on youtube.

Specify "somewhat low alternator output." There's a rule of thumb range but not a single right number.

By all means if the belt and tensioner are old, these matter to both the A/C compressor and the alternator. So if you want to keep a car on the road there's no reason not the change them out as a matter of maintenance. And then see what happens.

You didn't say anything (that I saw in the thread so sorry if I missed it) about how you charged up the A/C system. There is a sticker under the hood that specifies the precise amount of 134A refrigerant to install. Using the pressures is very imprecise. For an empty system, it should be installed by weight, not pressure readings. The readings you reported are too high on the low side and too low on the high side. The two most likely conditions there are low refrigerant or weak compressor.
 

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Discussion Starter · #13 · (Edited)
Both belt and tensioner are quite old and the vibration is shaking the car at idle when the A/C is on. The belt does not squeal, the tensioner's rattling noise is not annoying, but is noticeable inside the cab. I already ordered both Gates replacements.

I had edited my post about the now-working system, but I'll be more specific here:

I charged the system using a 1 Kg (35 oz.) R134A can and I weighted it before (1,267 g including two adapters) and during the charge. I stopped when the can weighted around 473 g (28 oz. = 794g, 1,267-794=473). I say "around" because I used a battery-operated kitchen scale to weight it, so there were some errors (the scale takes as 0 whatever weight it has while turning on, it turns off automatically after 3 minutes and I had to move the can while doing the charge, so the hose shifts the weight by some grams). I opened the low-side valve slowly to let the refrigerant in smoothly and rotated the can periodically from 0 to 90 degrees to let the refrigerant charge quicker. I didn't determine the charge amount by the pressure reading, but by the can's weight, only checking the pressures for any unwanted spike.

The pressures I'm reporting are the final ones I took after I let the car sit overnight and before I returned the manifold and vacuum pump. By the way, the low-side pressure was way too high on static (engine off), being around 80-90 psi.

By "somewhat-low alternator output" I mean around 13.4 V, sometimes less, but not below 12.4 V. I have a Bluetooth radio transmitter and there was an annoying "THE VOLTAGE IS TOO LOW!" alert with the car at idle and the A/C on, but it's not constant.

Thank you so much for your input.
 

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I'd say a new tensioner and belt are warranted given a perceptible noise.

As for the static, engine-off refrigerant temps, they're supposed to be "too high" on the low side with the engine off - actually just with the compressor off, engine running or not. With the engine off or compressor not running all of the refrigerant is vapor - takes up more space = higher pressure. The compressor liquifies that which does not want to be liquefied given the temps, but since it goes liquid the pressure drops due to lower volume. So you get lower pressure on the low (compressed) side and higher pressure on the high side. It's the shift from liquid to vapor that sucks energy - and thus heat - from the air.

At 80F R134a should sit about about 85-90-ish psi. So if the engine / compressor are off you should read about 85-90ish on both high and low side. If you run the car and kick on the AC, the low side should pretty much immediately drop to the 40-ish range and the high side should go to 175+ish.
 

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Discussion Starter · #15 ·
New tensioner and belt arrived and are installed; the rattling went away, of course, but I'm getting 11.3 V from the cigarette lighter while the engine is idling, so I might need to look for a new alternator too.

I'll take the car to an A/C shop tomorrow.
 

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11.3 is beyond dead charging system. definately have an issue there. but that wouldnt cause the ac to be not cold enough.. what exactly is the vent temp? before you take it anywhere you need to get the charging system figured out before it leaves you stranded.,
 

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If it really is 11.3 stranded is almost here. Surprised it's running. (Even at 12V a 12V battery is pretty much discharged). You said this was at the cig lighter. But did you check at the battery? Or at the alternator?
 

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Discussion Starter · #18 ·
It's an intermittent issue; I just ran the car again and it shows 14.3. I'll get that fixed, of course.

I haven't checked at the battery when it happens yet.
 

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Discussion Starter · #19 ·
Bumping because I just thought of something:

I installed an orange orifice tube and, checking my service information, it was supposed to be green. Checking online, they're supposed to be of different inner diameter.

This would cause the difference in pressures, wouldn't it?
 
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