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Low side port has high pressure reading

jettaguy on Thu January 31, 2008 1:18 AM User is offline

Year: 2001
Make: Volkswagen
Model: Jetta
Engine Size: 1.8t
Refrigerant Type: R134a
Pressure Low: 75

When I came back from my three week vacation, I found that my 2001 VW Jetta 1.8t a/c was not putting out any cold air. Later I also noticed a meldew like smell, fogging of the windows, and the passenger side carpet was wet. At first I thought maybe I ran out of refrigerant so I went out to get some. I bought a can with a gauge which was color coded. I followed the directions by turning on the a/c to high, shaked the can, and tried to blast some refrigerant into the low side port. However to my astonishment, I found that the pressure gauge read somewhere above the 65psi range. I tried to do some research and thought maybe it might be the expansion valve so I had a friend discharge the a/c. While discharging, we noticed some brownish liquid but thought nothing of it at the time. I replaced the expansion valve and tried to refill again but the gauge went quickly to slightly above 25 psi which indicates it was close to being filled according to the refrigerant. Now I'm stuck and I'm thinking maybe the problem is the evaporator. The compressor engages when the a/c is on and the fan is spins. I can't think of anything else so that's why I'm here asking for some professional advise. So any thoughts? Sorry for the long message but I wanted to be sure that I gave you all the pertinent facts.

Dougflas on Thu January 31, 2008 5:19 AM User is offline

You have made a few gross errors. First, before you added any refrigerant, you should have checked the high side also. You would need a SET of gauges for that. There is no reason to have to shake a can of refrigerant. When your friend let the refrigerant out of the system, did you pull a vacuum and did it hold? There was no mention of this in your post so I guess that was not done.

SUGGESTION.... from the AMA people, buy the book they sell along with their equipt for the beginner which includes a vacuum pump and guages etc. Now you'll have the min equip. to do the job. You'll also have to install a new drier.
Another option is to have a shop do the repair if you don't have access to equip. You may be able to use equip. from Autozone if there is oner near you. Either way, the job needs proper equip and proceedures.

NickD on Thu January 31, 2008 12:46 PM User is offline

That can you put in, still have it? Does it say anything about sealer being added or conditioner? That also has caused problems, not one AC manufacturer recommends that stuff. Best to stick with a name brand of R-134a, I prefer DuPont pure R-134a. You also may have lost some oil and could be adding lots of air to the system if you did indeed draw a deep vacuum first.

Always best to ask first before starting a project of this nature.

jettaguy on Thu January 31, 2008 3:44 PM User is offline

first of all thanks for the replies. So is your conclusion that the drier has gone bad? We didn't test to see if the vaccum hold because we thought it was the expansion valve at first. I know we were wrong so know I'll try and get a vaccum and some gauges to test the high side port. The can of r-134a didn't have any type of sealer or conditioner just the pag oil i think. hopefully i'll have some time to do the vaccum this weekend. thanks for the advice again.

Chick on Thu January 31, 2008 3:56 PM User is offlineView users profile

If only you could go back… The first problem was discharging the system without first checking if the compressor was engaged when you had the high low side reading.. Any compressor will show “equal” pressures on both sides if the compressor is not engaged. Best you can do now, is recharge it “properly” meaning pulling a deep vacuum and charging the system amount back into the vacuum. If the compressor isn’t running (center hub spinning with the pulley) then you know it’s another problem. If it is spinning and the high and low side are the same, or close, then you know it’s another problem. With Jetta/Golf of those years they used a variable displacement compressor in which the control valve is well known for sticking. After you recharge it, post back both high and low pressures and we’ll go from there..
Make sure the compressor engages when the AC is called for though..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

jettaguy on Thu January 31, 2008 6:00 PM User is offline

well i guess i'm in luck chick! the compressor was on when i had the high pressure in the low side port. Unfortunately i didn't test the high side port. I tried refilling after i replaced the expansion valve but the low side port reading on the r-134a can gauge kept reading that it was "filled". i know i made a big mistake by discharging the system before coming here. if only....

Chick on Thu January 31, 2008 6:21 PM User is offlineView users profile

Typically, the low side would drop into a vacuum when the expansion valve is clogged or stuck, so it is pointing towards the refrigerant control valve in the compressor, but try the Vac/charge procedure to confirm it. If that is the cause, those Sandens do not have user friendly control valves like GM, you have to dissemble the compressor to change them, so it it easier to just change the compressor You can e-mail the guys at Ackits.com to see if they have remans available..I didn't see one listed.. Hope this helps..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

NickD on Fri February 01, 2008 8:33 AM User is offline

I also get a bit nervous with refrigerant oil compatibility as to what is in that can and what is in the system, and do you really have to add more oil? These variable displacement compressors are nice as they are not continuously cycling on and off, much like the first POA systems that GM introduced way back in the 60's, but the are very difficult to top off. I say top off, because even the EPA states average R-134a leakage on passenger automobiles is about 10% per year. GM recommends you recover the charge, measure it, add the amount of pure R-134a to factory recommended specifications and dump it back in. But this requires a charging station. Topping off can be done, but helps to have lots of experience and should only be done on a very warm day, at least 85*F with manifold gauges, engine at 2,000 rpm, AC on, doors open, with the vehicle in the sun, and the blower at maximum. Then you are not relying on the just the gauge readings, but checking the outlet temperature of the evaporator, the heat of the compressor output, the feel of pulsations feeding the evaporator, carefully watching the high side and using judgement that comes with years of experience.

These kits should be outlaws, another thing teeing me off is this new 50-50 anti-freeze mix, so now have to run around looking for undiluted anti-freeze, in my neck the woods, I need a 60-40 mix. Swear these fluid vendors are smoking crack or just trying to find other means to screw you, charging just as much for water as for anti-freeze.

bohica2xo on Fri February 01, 2008 1:19 PM User is offline

Big old can o' worms here for sure.

Wet floor, mildew smells, fogged windows... More here than just a refrigerant loop issue.

That car has a complicated electronic control system to go with the variable displacment compressor. You need the "VAG 1551/1552 Scan Tool" to read the Climatronic's DTC's. A really bad DTC will cause the E87 display to flash for 15 seconds when the key is switched on. Some DTC's do not cause the display to flash...

Even with a compressor replacment, system flush, new dryer & recharge - you still have an issue going on in the cabin system. While the system is empty would be the time to pull the evaporator and find out what is wrong mechanically that is causing the wet floor.

B.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

jettaguy on Sat February 02, 2008 1:20 AM User is offline

well i'm gonna try and vaccum the system and see what happens. i haven't found a place to rent a system so i may have to take it to a shop. the only thing is i hope it ain't the compressor because that'll be some big bucks to shell out! by the way, i guess i'm sorta lucky because i don't have a climatronic system. i have a manual a/c system and no codes came up when i scanned it in the beginning.

NickD on Sat February 02, 2008 11:28 AM User is offline

Could also be a plugged drain on the evaporator case causing the mildew and wet floor.

Why do they plug? It's because they were designed to do that, you get debris sucked in the fresh air intake or even the recir intank that goes through a chopper, well, they call that a blower motor, it chops up say a piece of gum wrap paper or a leave that deposits itself on the evaporator case floor, condensation washes that down the drain and plugs it.

What is the solution? To install a much finer blade squirrel cage blower wheel that chops this debris into a powder form that can be easier to wash down. Or just clean the drain until it happens again. Ha, you can hear those engineers laughing when they really made cleaning that drain a miserable job. Let's see if we can even make it twice as difficult in next years model.

abossram on Sun February 03, 2008 8:44 PM User is offline

Are you losing any coolant? Kinda sounds like a possible heater core leak- if you have antifreeze in the radiator and the heater core is leaking, you will have window fogging and an antifreeze smell inside the car! Let us know if maybe what you smell inside could be antifreeze-otherwise, the prior poster is correct about the drain for the evap case being plugged for that part of the problem-then back to the main prob. Good luck!

jettaguy on Mon February 04, 2008 2:23 AM User is offline

unfortunately i couldn't find a place to rent out the proper tools to vaccum the system this weekend. as for the coolant problem, i don't have any coolant leak. I looked at the coolant level and it's ok. i talk to this parts guy at the volkswagen dealership and he said that the heater core is the most common problem with the a/c. is the heater core the same as the evaporator?

bohica2xo on Mon February 04, 2008 10:41 AM User is offline

The heater core is located adjacent to the evaporator, but is not the same thing.

Like I said before, the wet floor is a seperate issue from the refrigerant loop. Both problems need to be addressed. You should read up on refrigeration repair, and auto repair before going any farther into this.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

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