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Gen 1 AC Refrigerant Refill Tips

Discussion in 'Generation 1 Prius Discussion' started by VOR, Jul 18, 2016.

  1. VOR

    VOR Junior Member

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    Hi Everyone,
    Just a few weeks ago got my 2001 Prius back after my father-in-law replaced the bad stator (I have no garage so that extensive of a repair waand we had a wiring harness issue repaired. It's been running good so now I want to tackle some of the other more minor issues the car still has.

    Next on the list is the AC (Its is not blowing as cold as it should).
    * No blinking AC light so I don't think checking for AC codes will even work (correct me if I'm wrong).

    * Car has approx 167,000 miles on it so refrigerant being low is a definite possibility (to our knowledge it has never been recharged).

    Questions:
    1. What should I look for in the sight window/glass to check if my suspicion of low R-134a is correct?

    2. Checking through previous AC posts it looks like using R-134a with any kind of leak stop is a bad idea?

    3. What should I look for and/or avoid when choosing R-134a and a refill gauge?

    Thanks
    Vance
     
  2. ChapmanF

    ChapmanF Senior Member

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    I had never added any refrigerant to my Gen 1 by 238,000 miles, but the compressor clutch definitely needed reshimming before then. When you measure the clutch plate pull-in with a dial indicator, it should be around half a millimeter (0.35 to 0.65 mm is ok). Mine had been worn all the way out to 1.34 mm before the performance was noticeably flaky, and it's a very simple, cheap adjustment.

    With that out of the way, if you still think refrigerant is an issue, you should see few to no bubbles when the compressor is operating, except for some right when it starts or stops ... assuming you are checking under the specific conditions you find in the manual ... under different conditions, the bets are off. The proper charge is to add another 100 grams of refrigerant past where the bubbles stop, under the specified conditions, therefore when it is properly charged, you should expect to see a pretty solid, bubble-free stream, under the same conditions.

    -Chap
     
  3. VOR

    VOR Junior Member

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    Hi Chap,
    Always glad to see you on one of my posts! Unfortunately, I don't think I have access to the dial indicator you mentioned. Can provide a web link showing this tool so I can see a picture of it and get an idea of cost.

    I didn't see any bubbles at all. In fact I didn't see any flow at all until I shut down the AC system. Maybe I didn't run the system long enough. How long should the AC be running before checking the sight glass?

    As for the manual. I noted in some of the other AC posts you talked about downloading the manual. Is the download of the manual okay with Toyota or do they specifically prohibit this even though it's possible download and save the manual to your computer? I know most people don't care but I want to make sure my downloaded copy of the manual will be legal/legit before giving up my $15 for the access. If Toyota doesn't give the download permission I'll just keep up my search for printed manuals.


    Thanks,
    - Vance
     
  4. ChapmanF

    ChapmanF Senior Member

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    The sort of Harbor-Freight-quality dial indicators, complete with a magnetic articulated base and selection of tips, seem to be available in the twenty-dollar neighborhood nowadays, and as long as you are not a machine shop beating on them every day, should serve you well for all kinds of the usual dial-indicatory tasks around a car (checking your hub or brake rotor runout, bearing and joint play, etc.). One of those tools you don't necessarily appreciate the frequent handiness of until you have one.

    As for the techinfo terms of use, if I remember right, you can find them before you pay, and make your own judgment as to what use on your part would be within their letter and/or spirit. Since you have a 2001, you do have the option to go for the printed manuals if you prefer; I think it's only the 2011s and newer that have techinfo as the only option.

    The refrigerant is clear, so clean-flow-without-bubbles is pretty hard to tell apart from no-flow. It's only when bubbles go by that you see anything happening. If it looks like nothing is happening while the compressor's in motion, but you then see a little burst of bubbles when it shuts off, that sounds pretty close to proper charge (assuming, again, the ambient temperature, engine speed, and all other conditions as spec'd in the manual).

    -Chap
     
  5. Brian in Tucson

    Brian in Tucson Active Member

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    I've been doing my own A/C work since the 80's, with my own manifold & gauges, vacuum pump, etc. When I got my Classic Prius, the a/c worked but not very well. Everything checked out, just needed some refrigerant. I read about how PAG oil will contaminate the system and under no circumstances allow any to get in. So I went out and bought a mini a/c system A/C Pro--acp-400 (I haven't been here long enought to post a link.) Note, it says "not for hybrid vehicles with electrical driven compressors. Our first gen. Prius are belt driven, so it should be okay. This recharge tool has some excellent features: 1/ the tool has a trigger so that you can put small bits of 134a in at a time--you don't want to dump 11 oz in at a time, this valve lets you put it in an ounce or so at a time. 2/ it has an easy to read guage. You want to put freon in a bit at a time, but keep the system pressure in the safe zone on the guage. 3/ the low side connector is easy to use, and to remove. 4 the tool seems to hold the pressure in the can for use later.

    I think I only had to add about 3 oz or about 80 grams. A/C will almost make popsicles now.
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    If you didn't see any bubbles it can either mean it's well charged, or there's nothing at all in there. If it's clear while running, then a swirl of bubbles as the compressor shut's down, I would think you've got no problems there. I almost prefer to see the occasional stray bubble as it's running, just reassuring.
     
  7. Brian in Tucson

    Brian in Tucson Active Member

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    First some cautions. The system on the Prius uses a totally different lube from other automotive system. Absolutely no PAG oil!!!!

    Don't use equipment that's been used on conventional automotive A/C. It's contaminated and using it can cause a whole world of hurt. It's a standard R134a fitting. This is the tool I bought specifically for my Prius 1. A/C Pro C Pro / Recharge hose and gauge - Not for Hybrid vehicles with electrical driven compressors ACP-400- ReadReviews onA/C Pro #ACP-400

    [​IMG]upload images

    Note that it has a gauge, a trigger, and an easy to use R134a low side connector. The trigger seems to hold pressure, I've had a pressurized can of pure R134a connected for about 3 weeks One can of R134a will fill the Prius 1 system, you want to use the plain refrigerant, no sealers, dyes, or oil charge. I guess I'd take the car to a standard A/C shop, fill it with your recharge equipment and let them use a freon sniffer to find your leak(s), but don't let them replace any o-rings, they'll want to lube them with PAG oil. :( I keep my new filler in a ziplok bag when not using it. You can get a pretty good freon and halogen detector from Harbor Freight for $69 minus 20%--a nice tool to have. Electronic Freon and Halogen Leak Detector

    Best, tho, to take it to a hybrid shop, either Toyota or an independent.

    With the engine running and the A/C on and set to its coldest, give the system short shots of R134a. You don't want to over charge, so anything over about 36 psi at the low side connector is not advised. Trying to find the leaks with soapy water might work, but doing it with a sniffer is a better solution. If you replace parts, you'll need to pull a vacuum, and I think the best thing is to let a Hybrid trained tech do this work.

    Hope this helps.:D
     
  8. ChapmanF

    ChapmanF Senior Member

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    This is a thread about the Gen 1 A/C system, in the Gen 1 forum, so that doesn't apply. The high-voltage electric A/C systems requiring ND-11 oil started with Gen 2.

    The conventional, mechanical compressor in Gen 1 uses ND-8 oil "or equivalent" (see page AC-49), which seems often equated to PAG-46 (I'd be more sure I found an actual Denso page that says so, and I haven't, but vendors seem to agree about it).

    And yes, if you have a Gen 2 or later Prius requiring ND-11 oil, then be sure to use only that. But this thread's about Gen 1....

    -Chap
     
  9. Sandy Meyers

    Sandy Meyers Member

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    HI Brian, it’s Sandy in So Cal with the Generation 1 and now 96,000 miles.
    I’m in Palm Springs where it’s about 100 quickly approaching 109 this week and my AC is kaput! Since I normally reside in Long Beach, I’ve not really noticed my AC, but the car is nowhere near cooling.... it’s trying, but it cannot deal with this heat. I’ve got no error codes. A new friend here told me he could help recharge, but I thought I would investigate here first.
    I don’t want to screw up my system with a foolhardy neighbor who doesn’t know hybrids yet who is eager to help.
    Any recommendations on how to get started? I think we can do this together but I want to go about it correctly.
    Many thanks.
     
  10. ChapmanF

    ChapmanF Senior Member

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    Hi Sandy,

    Pretty much any Gen 1 is old enough now for the compressor clutch to be slipping. The shim kit to correct that costs one dollar at the dealer, and it is a ten minute job. If you are starting with poor cooling performance and have no other specific reason to suspect the refrigerant charge, the ten minute one dollar clutch job is the absolutely first place I would look.

    After ruling that out, refrigerant charge could be a next thing to check, if there's still an issue.
     
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  11. jb in NE

    jb in NE Senior Member

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    There is no difference in the A/C setup between this car and a non-hybrid. Any competent HVAC tech with a recovery unit, set of pressure/vacuum gages, and an accurate scale can work on this. Evacuate the system, pull a vacuum to check for leaks, if none than recharge with a full charge of freon per the label under the hood. That's pretty much it for the refrigeration loop.
     
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  12. ChapmanF

    ChapmanF Senior Member

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    In fact, any competent HVAC tech who is old enough will remember that compressor clutches wear out (they've worked the same since 1954 Pontiacs), and will check for the one dollar, ten minute fix before bending your ear about ever-lovin' refrigerant recharges.

    But a lot of them are not old enough, plus they can bill you more for the refrigerant and the labor-intensive recover-vac-and-charge.
     
  13. jb in NE

    jb in NE Senior Member

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    Any competent HVAC tech can tell in two seconds whether the clutch is working. If it is, they fix it. If not, then they check the refrigerant pressures and in most cases find that the car needs a recharge, as these systems inevitably have some leakage.

    Consistent with the comment that "Its is not blowing as cold as it should". Which indicates that it is blowing somewhat cold (which would rule out the clutch), but not as cold as usual.
     
  14. ChapmanF

    ChapmanF Senior Member

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    It takes a little more than two seconds, if not that much more.

    The clutch does not have a binary failure mode (works or doesn't work).

    As it becomes worn, it loses some of its ability to transfer torque. It will appear to work just fine at low engine speeds or moderate loads, but will slip, transmitting less power to the compressor, at higher head pressures, higher RPMs, or both. This will still look like it is spinning, to the unaided eye, and give you exactly "It is not blowing as cold as it should", just somewhat cold, which therefore in absolutely no way rules out the clutch.

    Gen 1 is designed so it can give you an HVAC code 22 if the clutch slips enough to meet the code threshold. The compressor has an RPM sensor, and the ECU compares its RPM to the engine RPM (accounting for the ratio of pulley sizes), and if the compressor is making less than 80% of the RPM it should be, for three seconds or longer, the code 22 will set. This is not the kind of judgment that any HVAC tech, however competent, is going to make successfully by glancing at the clutch to see if it looks like it's spinning or not.

    Even the ECU's code 22 is less helpful than it could be. If you get the code, you know you have a clutch issue (or possibly belt, though belt slip often makes a horrible shriek, unlike clutch slip). But it's very possible to be suffering from a slipping clutch without ever catching the codes at a time when the 22 is remembered.

    The competent HVAC tech will stick a dial-indicator base to the engine block (engine off) with the plunger riding on the clutch disk, temporarily pull out the clutch relay in the fuse box and jumper across the terminals, and watch how much the dial indicator moves.

    For the Gen 1 clutch, the spec is 0.5 mm, with 0.35 to 0.65 being acceptable. It can usually wear well outside that range (to two or three times the spec, 1.0 mm or greater) before you notice lousy cooling. It takes ten minutes to fix.

    The youngest Gen 1 Prii in existence are sixteen years old. The clutches are known wear items in normal use; that's why Toyota has a one dollar shim kit to readjust them.

    Some cars will be leakier than others; some will never need refrigerant added in their useful lives. But the clutch wearing out is just like death and taxes.

    If you find an A/C shop where the techs are old enough, none of this is news to them.
     
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  15. jb in NE

    jb in NE Senior Member

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    Good info. Thanks.
     
  16. Sandy Meyers

    Sandy Meyers Member

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    Thank you for all the info.
    Can anyone tell me if this #36 50 A fuse, an AC fuse is blown? I’ve checked all the others and they appear okay, but this one is baffling.
     

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  17. jb in NE

    jb in NE Senior Member

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    It's hard to tell from that picture. Here is a sketch of that Type C fuse from a Gen 4 owner manual showing the difference between a good fuse and a blown fuse. The best way to tell is to put an ohmeter on the contacts and see if there is continuity. If yes, the fuse is not blown.

    upload_2019-6-9_10-14-16.jpeg
     
  18. Sandy Meyers

    Sandy Meyers Member

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    Thank you for the fast reply.
    Mine appears more like #2. Could this likely be the root of my AC problem? My #37 and #38 look similar.... but I have no dashboard error codes. Odd to me.
     

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  19. jb in NE

    jb in NE Senior Member

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    From your original post, you noted that "the car is nowhere near cooling.... it’s trying, but it cannot deal with this heat." This is typically not consistent with a blown fuse of that size. With a blown fuse, it shouldn't work at all. If it is working and not cooling as much as it should, then I would be looking at the clutch, refrigeration levels and pressures, etc.
     
  20. Sandy Meyers

    Sandy Meyers Member

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    Thank you.
    In thinking about this, it’s been so long since I’ve had real genuine AC. I do not drive my car much on a daily basis at home and I live in a climate where I don’t require AC, I cannot say for certain if in fact the AC is really “trying to work.” That might have been a more hopeful comment in retrospect. In 100 degree heat, any fan action feels like AC. On this last trip I went from a climate in 68 degrees to 100, so it is difficult to say what’s really going on here if I’m getting genuine AC that was blowing or just cool climate breezes. It’s definitely not working here in Palm Springs as I sit.

    I don’t have the required tools to test the fuses on me here so I’m stuck. I can go buy fuses at Autozone to start with the simple stuff.

    Thanks for all your help here.