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#16
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Hi Bob-
The sight glass is just too dark to see ANYTHING.... :-( With R-134, I believe the pressure should be about 80-85 lbs.(both sides) with the sytem off, and 20-35 lbs low side / 150-250 high side with the compressor running. Please correct me if that's wrong... If anything, I've got a touch too much pressure, but that wouldn't be the cause of there being no differential while it's running. At least it's not leaking out, but I still need to fix something here... :-( Thanks.
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Barry |
#17
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At the 98 degrees indicated in your first post, you should have 120 psi botyht sides with the compressor off and the car just started.
Here is a pressure/temp chart even if somewhat hard to read. http://www.prevostcar.com/DB/services/maintenance/Maintenance%20du%20syst%E8me%20CVC.pdf#search='r134a%20pressure%20chart' |
#18
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Are your gauge handles closed (they should be)when you are taking the pressures? Have to ask,
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The Golden Rule 1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later) |
#19
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on my 91 190 the ac compressor had a gasket on the manifold where the high and low pressure hoses connected which seperated the two sides. the gasket had pushed out in the center portion (probably from the prev owner overcharging the system) and was letting some of the high pressure bleed over to the suction side. my guage readings were pretty close to yours.
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"the simplest answer is usually the correct answer" 1991 190e, 2.6 (helga) 91,000 mi |
#20
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Oh no, GOOD call on the gauges being OPEN..... LOL!!
(sorry, it's been a few years since I've had to work with A/C systems - and I just wasn't thinking....) :-( And that Pressure Chart is VERY interesting..... In Houston in the summer, depending on what time of day (and the weather) you check the pressure, it could be 75 degrees, or 100 degrees..... I had no idea the ambient temp affected the pressure THAT much.... Let me try this again tonight - a MUCH better informed amateur tech this time... Thank you for your patience....
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Barry |
#21
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Well.....
Good news, and really terrible news..... :-( The guages being open was "my" problem, and easily fixed..... The freon had basically completely leaked out.... I was reading the pressure in my "tank", not the car's system.... DOH!! Added some freon, brought the pressures up to (at 90 degrees ambient) 60 lbs. on the low side, and 260 on the high side.... We had cool air, and all is well..... Almost...... Anybody ever seen freon actually "drip"?? Drip so much your first thought is "I can't believe the heater hose just sprung a leak"?? It wasn't the heater hose..... :-( I have a steady "drip" of freon, and (here's the really bad news) the drip is back by the transmission - pass side..... I didn't get under the car, but I can see it dripping just by looking down from the engine compartment..... There's a PUDDLE of freon on my driveway.... That would be the Evaporator core, correct?? And that's the one that is like $3500 to repair?? PLEASE tell me I'm wrong...... :-( I love the car, but I'm sick about this...... Thank you ALL for your help. Each step brought me closer to finding the REAL problem - Bad evaporator, and operator error.... :-(
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Barry |
#22
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A Puddle of freon in the driveway ..
I've heard them all , now.. Think maybe you have condensate coming from an operating system.. |
#23
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I WISH I was kidding....
It's green, and it has no smell, nor is it oily (like I'm sure coolant would), and it didn't start until I filled the A/C system with freon..... Tonight I have reasonably cool air.... I'll let you know how long it takes to leak down....
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Barry |
#24
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R-12 freon at normal pressure will boil at -21 degrees F. Were it cold enough for Freon to remain liquid outside a pressurized container, you would not be worrying about your A/C.
From your pressure readings, it sounds like you may have over-charged the system a bit. Was the system completely empty? And did you then evacuate the system prior to charging?
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1989 300 SEL that mostly works, but needs TLC |
#25
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Well, it's R-134, and I can assure you it didn't leak "coolant" BEFORE I filled it with freon tonight, and yet I'm watching green liquid drip down right beside the transmission as I'm finishing up charging the A/C system.
SOMETHING is green in my 30 lb. tank of R-134, and it's green leaking onto my driveway. Maybe it's not the freon itself, but it's coming from my A/C system, NOT the cooling system..... To be otherwise is just TOO big of a coincidence - and the coolant overflow tank level is holding steady..... I'm just telling you what I'm seeing - a problem that DOESN'T involve the evaporator would be a blessing as far as I'm concerned.... If I drive it for the next few days and it stays cool and my coolant level drops, then I'll be happy to admit I am wrong, but I don't think thats what's going to happen.... :-(
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Barry |
#26
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R-134a also boils at way low temperature. I don't happen to know exactly how low. but I'd wager it's also well below 0 degrees F. Both R-12 and R-134A are colorless, unless somebody added a leak detection dye at some point. Green, to me says antifreeze, except I understand MB uses a different color. The only thing that could possibly leak from your A/C system, and remain liquid long enough to puddle on the ground, would be the oil. Either case (antifreeze or A/C oil) leaking from that area would require a major repair, so it would be best to make certain what it is you're seeing. If it's just condensation, no worries...although I'd be curious as to how it turned green.
I'd rather believe it's just a coincidence than believe that you've somehow violated the laws of physics and created liquid refrigerant at standard pressure and summer temperature.
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1989 300 SEL that mostly works, but needs TLC |
#27
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I'm sure you're correct about an additive, because I realize that freon is both colorless and odorless, and is a vapor at room temperature.
And while the tank only labels it as HFC-134A, there is certainly something that is green mixed in with the freon in my tank. And that's what I'm sure is also coming out back by the transmission. I haven't been under the car yet, but there are only two things that I can think of that would be leaking green liquid back there - the heater core, and the A/C evaporator core (filled with freon with a green additive). I just haven't had any problems with the cooling system (no leaks whatsoever) and all of a sudden I'm adding freon (with a green dye mixed with it) and at the same time I have green fluid dripping down back by the transmission. Like I said, I'm going to give it a few days to see what the a/c does, and also keep an eye on the coolant tank, but it took me by quite a surprise to witness what I saw....
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Barry |
#28
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Just an update.....
The coolant level hasn't changed, and now almost a week later I still have reasonably cool air, so must not be any major leaks coming from the A/C sytem either.... Which was my major concern.... So, the fluid coming out of the drains was certainly mostly condensate, but it was also definitely green. And there is only two green fluids that I know of going INTO the car - engine coolant, and the freon I added also has a bright green additive in it too.... In over 1000 miles of driving, the coolant level looks to be exactly where it was when I bought the car, so I'll presume I'm okay there.... I am obviously still going to watch this, and cross my fingers that the air blows cool for quite a while, but hopefully my worst fear of a condenser issue may have been unwarranted.... :-) I really need to park the car in one spot for 10-15 minutes with the A/C running from time to time, and then see what kind of puddle is under the car.... And yes, I know... CLEAR water is good.... LOL!! Onto my NEXT problems for now.... :-( Thanks.
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Barry |
#29
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If you have the right coolant in the Benz its not green.
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Proud owner of .... 1971 280SE W108 1979 300SD W116 1983 300D W123 1975 Ironhead Sportster chopper 1987 GMC 3/4 ton 4X4 Diesel 1989 Honda Civic (Heavily modified) --------------------- Section 609 MVAC Certified --------------------- "He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche |
#30
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The green is prob mildue that finally got washed off the evaporater cuz you now have condensate. The condensate drains are on the sides of the tranny, so that is definately H20..
.. if you can get that freon to drip into a puddle , go see the guys at NASA , .. they want to talk to you.. |
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