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Thread: Water under the car

  1. #21
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    To add to the confusion, because I don't think it's been 100% spelled out in this thread, it's not uncommon for the drain hose to get caught up around the frame for whatever reason. This happened on mine, and
    the passenger side was filling with water. If you can't see it from underneath, it's worth looking in the access panel under the spare. I also ran picture wire (which has endless repair uses on a DeLorean) up
    mine to clear and potentially clogging, at least to the elbow.

  2. #22
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    A lot of info to take in. I'm not good at the quoting function. So first you guys that posted pics, now I see the tube. (At least in the pic, haven't looked on the car yet)

    Ron, I'm having trouble with that chart. It has a column for AC discharge. I've not seen that term before. Would that be at the shrader on the accumulator? Is that where you guys take your readings? I took my readings at the compressor and it was only a 70 degree day. I wanted to wait till it was 90 out before adding freon.

    It might not seem like it, but I am actually very experienced in refrigeration, but not auto AC. My wife and I owned a restaurant/bar and there a ton of refrigeration stuff in that business, so I took a course. I own all the tools. This is my first R12 system.

    When I was working on the AC, it did seem to cycle a lot. I worried that it might ware out the clutch. But again, I didn't want to do to much till it was 90 out.

    I've got some other pressing projects right now, so I must park the car for a couple days. I'll be back on it shortly.

  3. #23
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    Quote Originally Posted by Helirich View Post
    When I was working on the AC, it did seem to cycle a lot. I worried that it might ware out the clutch. But again, I didn't want to do to much till it was 90 out.
    Mine certainly cycles a lot; I understand this is common. It took me nearly a year to figure out the ~30 second clicking from the engine bay was in
    fact the clutch. As an aside, Dave McKeen's fan relay helps avoid the fans cycling quite as much with the A/C.

  4. #24
    Administrator Ron's Avatar
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    +1 Bitsy, DMC-Ron, MrChocky

    Quote Originally Posted by David T View Post
    The Delorean has an unusual design to keep the evap coil from freezing. The pressure switch is set so that the compressor will cycle on and off allowing the evap coil to clear any ice. It also allows the radiator fans to stop so they don't run continuously. If you don;t adjust the system to cycle the evap coil freezes up and you overload the electrical system. You can make sure the drain is clear by taking the fan motor out.
    EXACTLY!

    Quote Originally Posted by Helirich View Post
    Ron, I'm having trouble with that chart. It has a column for AC discharge. I've not seen that term before. Would that be at the shrader on the accumulator? Is that where you guys take your readings? I took my readings at the compressor and it was only a 70 degree day. I wanted to wait till it was 90 out before adding freon.
    The column is for the air temp expected at the cabin duct output. (Double click the chart to enlarge it.)
    Yes, take other readings at the compressor.

    Quote Originally Posted by Helirich View Post
    It might not seem like it, but I am actually very experienced in refrigeration, but not auto AC. My wife and I owned a restaurant/bar and there a ton of refrigeration stuff in that business, so I took a course. I own all the tools. This is my first R12 system.

    When I was working on the AC, it did seem to cycle a lot. I worried that it might ware out the clutch. But again, I didn't want to do to much till it was 90 out.

    I've got some other pressing projects right now, so I must park the car for a couple days. I'll be back on it shortly.
    .
    FWIW- I wasn't thinking what you seem to think I was thinking...I think the latter part of the discussion got off track over my (obviously poor wording/explanation). But, in my defense, I never used the term "Low/High switch" . (I edited it with changes in red, Please reread ).

    Maybe starting from scratch with an example will help clear things up:
    Given:
    The system is stock, sound and evacuated.
    R12 refrigerant.
    Ambient 70F (Box fan at radiator!)
    Pressures and temps taken when clutch cycles out.

    What I would expect:
    When you turn the AC on, nothing happens. As you introduce the charge, both sides rise above ~60 psi (equalizing through the orifice tube), causing the cycle switch to turn the clutch on. The compressor will take from the low side and add to the high side. The low side will fall below 32-35 psi as the high side rises, causing the cycle switch to turn the compressor back off. Equalization will begin. The equalization (and the charge continuing to flow in) will bring the low side back above 60 psi, the cycle switch turns the compressor back on. This repeats until the charge is complete. .
    From here (once settled down), the compressor takes from the low side, pulling it below 32-35 psi as it raises the high side to 220 psi. The cycle switch will turn the clutch off. Equalization, through the orifice tube, will bring the low side back up above 60 psi...and this repeats forever, as long as the ambient remains the same. The output at the ducts should be ~36F.
    (Note, as I mentioned before, I find the high side pressures to be higher than the chart where I live, using the exact charge called for. FWIW- I believe it is ruff field data, very ruff...maybe from a Volvo
    As I suspect you may already know/find interesting:
    If conditions are just right, the clutch will never cycle.
    Although the chart is checking data, you can use it to top off/charge the system in an "emergency". Don't quote me on that! )

  5. #25
    Administrator Ron's Avatar
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    Quote Originally Posted by MrChocky View Post
    Mine certainly cycles a lot; I understand this is common. It took me nearly a year to figure out the ~30 second clicking from the engine bay was in
    fact the clutch. As an aside, Dave McKeen's fan relay helps avoid the fans cycling quite as much with the A/C.
    There is a little screw between the two electrical terminal for the cycle switch you can turn to help that.
    Warning: This should only be done with a gauge set connected and a little goes a long way. And always double check the pressures on the hottest of days.

  6. #26
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    Quote Originally Posted by Ron View Post
    There is a little screw between the two electrical terminal for the cycle switch you can turn to help that.
    Warning: This should only be done with a gauge set connected and a little goes a long way. And always double check the pressures on the hottest of days.
    You should only adjust that screw after filling the system with the exact amount of R-12 and making sure everything else is operating correctly. The coils are clean, both radiator fans are working, etc. DO NOT adjust that screw to compensate for an over-filled or under-filled system. If you convert to another type of refrigerant you do need to adjust the pressure switch but unless it was messed with it should not need to be adjusted for R-12. Working with R-12 is just like any other refrigerant, use the tables to confirm operation but to fill you should measure it in by weight. My system had a minor leak and I got tired of topping it off. I used a leak sealing kit and now it is perfect. The leak sealing kits today really do work. Before filling you should replace the service valve cores, drain and refill the compressor with fresh oil and pull a hard vacuum. If you have original hoses you should replace them and the accumulator (it has the dryer inside). A car's A/C can't work well unless the motor's cooling system is PERFECT. Make sure the cooling system is working as good as you can or you will have problems with the A/C too. As for the cycling, the system was made to handle it but you should check the gap on the clutch and adjust if necessary. All of this is in the Workshop Manual.
    David Teitelbaum

  7. #27
    LS Swapper Josh's Avatar
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    Quote Originally Posted by DMC-Ron View Post
    Agreed. I've never seen a combo low/high pressure switch. Our systems have the low pressure switch. I've heard some owners add a high pressure switch but it's likely unnecessary. In order for the compressor to generate a high pressure it must pull the suction down to a low pressure. The low pressure switch would cut out before the high side became excessive. The exception would be if there was way too much refrigerant in the system. An overcharged system would elevate the suction pressure and prevent the low pressure switch from providing the high side protection.

    Ron
    You cannot have a combo switch because the low pressure switch is on the low pressure side of the system (larger hose), after the orifice tube.
    The high pressure side of the system (the smaller hose) is before the orifice tube, and can see pressures close to 400psi under extreme situations. If you do not have a high pressure switch and the system overpressures (can be something as simple as the radiator fans not starting with the ac) pressures can approach 500psi within a few minutes and if there is not a relief valve you can blow a hose or damage other portions of your ac system.

    Supercharged 5.3L LS4 + Porsche 6spd
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  8. #28
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    Quote Originally Posted by David T View Post
    The Delorean has an unusual design to keep the evap coil from freezing. The pressure switch is set so that the compressor will cycle on and off allowing the evap coil to clear any ice. It also allows the radiator fans to stop so they don't run continuously. If you don;t adjust the system to cycle the evap coil freezes up and you overload the electrical system. You can make sure the drain is clear by taking the fan motor out.
    So, what kind of cycle times should I expect? Mchocky mentioned 30 sec. would you say that is operating correctly?

    Quote Originally Posted by Ron View Post
    The column is for the air temp expected at the cabin duct output. (Double click the chart to enlarge it.)
    I see said the blind man as he picked up his hammer and saw.

    Quote Originally Posted by Josh View Post
    You cannot have a combo switch because the low pressure switch is on the low pressure side of the system (larger hose), after the orifice tube.
    The high pressure side of the system (the smaller hose) is before the orifice tube, and can see pressures close to 400psi under extreme situations. If you do not have a high pressure switch and the system overpressures (can be something as simple as the radiator fans not starting with the ac) pressures can approach 500psi within a few minutes and if there is not a relief valve you can blow a hose or damage other portions of your ac system.
    Wow, I agree with everything you just said. I guess there's hope for us yet.

  9. #29
    Guru butcher Michael's Avatar
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    Quote Originally Posted by Helirich View Post
    So, what kind of cycle times should I expect? Mchocky mentioned 30 sec. would you say that is operating correctly..
    Even with a correctly charged system cycle times are not etched in stone. It's about pressure. You may have a compressor that is not as strong as the next guys, or a r12 system converted to 134 woll probably not be as efficent as a newer one designed for 134. With a properly charged and functioning system, your compressor should engage around 37psi and disengage around 25(I don't have the exact numbers in front of me but I'm sure someone will correct me if I'm off so much as one degree).

    Your system may cycle regularly at highway speeds but may not cycle at all at idle because the pressure may never gets low enough, especially with a retrofitted system.

    It's not an exact science since so many of us have compressors not original to the r12 OE system.

    Mine is a bit of a bastard child. I have my pressure switch set just a tad higher as mine is converted from r12 so I don't have to worry as much about freezing. Mine will still cycle but not as often as it did when I was on R12.
    http://dmctalk.org/image.php?type=sigpic&userid=90&dateline=161808992  9

  10. #30
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    Quote Originally Posted by Michael View Post
    I don't have the exact numbers in front of me but I'm sure someone will correct me if I'm off so much as one degree.
    Got to love the Internet. Lol

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