# 1997 Jetta GL A/C problems???? HELP!



## redcabriolet89 (Nov 2, 2003)

I drained and recharged the A/C with new A134. The clutch on the compressor kicks on and it still blows luke warm air. Not sure what else it might be. Maybe a valve on the compressor is no opening. definitely no leaks, so I already ruled that out. All wireing commections look good. Can't seem to figure out what else it could be.


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## redcabriolet89 (Nov 2, 2003)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

I looked at my Bently manual last night and I am going to check a few things. Cross my fingers......


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## mrdub27 (Mar 25, 2002)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

problem... you drained the system.. did you have it vacated of air and moisture..? if there is reg air in it then it will not function properly at all.. how did you drain it.?? Vent to air.?? have someone vacate the system properly then recharge it .. that might be the difference.. you still have air in it ..


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## redcabriolet89 (Nov 2, 2003)

*Re: 1997 Jetta GL A/C problems???? HELP! (mrdub27)*

My neighbor just drained it to air. He is a retired heating and air guy, but I don't think he knows auto a/c systems like he claims. Could that really be the problem????


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## jorge r (Apr 27, 2006)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

regrigerant mixes with air, vent the refrigerant and the air at the same time.
Needs to hook up a set of gauges and check the pressure. Does the refrigerant come back cold to the compressor, is the suction line cold?


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## bearing01 (May 27, 2004)

*Re: 1997 Jetta GL A/C problems???? HELP! (jorge r)*

You must pull a vacuum on the system to get the air out before recharging. Also, when letting out the old refrigerant, often you can get some oil loss with the refrigerant considering the oil is carried by the refrigerant.
You must make sure you add the correct weight of refrigerant to the system. That means you need a scale to do it.


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## germancarnut51 (Mar 23, 2008)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

Why did you dump the refrigerant in the first place? Refrigerant does not age, it just gets contaminated over time, if the recevier/dryer goes bad (which required replacement if it happens).
You need to get an ac manifold gauge set ($45 from Harbor Freight)to see what's happening in the ac system, BEFORE you do anything. If you are unwilling to buy a gauge set so you can see what's happening, pay a shop to do the work.
If an ac system leaks, all you need to do is add refrigerant to bring the refrigerant level back up. No need to drain the system.


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## redcabriolet89 (Nov 2, 2003)

*Re: 1997 Jetta GL A/C problems???? HELP! (germancarnut51)*

Yeah I am ready to just take it some where.


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## vw1016 (Aug 5, 2009)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

It might be an ambient Temp sensor


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## redcabriolet89 (Nov 2, 2003)

*Re: 1997 Jetta GL A/C problems???? HELP! (vw1016)*

Tested some things tonight.......







.......Ok, High pressure switch is working fine(clutch is on), refrigerant is at the correct level(I refilled it with the kit that has the built in gauge, the a\c cut-out thermal switch is working(fans are on), the expansion valve gets cool and begins to sweat a bit, but the high pressure service line never gets cold. I does how ever seem to surge every now and again.







I'm not sure if the expansion valve could frezze up? I tapped the expansion valve with a small hammer and it never seemed to open. Not sure what to try now????????







Now it's time for










































http://****************.com/smile/emthup.gif


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## redcabriolet89 (Nov 2, 2003)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

Not sure if ambient temp sensor would pertain to my problem. I have another one here to swap out with. It look like a bit of a job to do, but if anyone thinks it is definitely the problem I'll get startrd right now.


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## bearing01 (May 27, 2004)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

All the lines on the low pressure side (the bigger diameter lines / tubes) should feel cold and wet like a beer can. All the lines on the high pressure side (small diameter tubes) should feel really hot to the touch.
As for surging? You need to put a real manifold gauge on both the low side and high and look at both pressures simultaneously. That could tell you if it's bad valves in the compressor or if you have a blockage somewhere. If it were a frozen / ice internal blockage then that would suggest moisture in the system. I would expect it to freeze and stay frozen until the system was turned off and allowed to thaw.


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## vw1016 (Aug 5, 2009)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

Well i had a similar problem with my car and I found that It was the ambient temp sensor. It def took care of the prob.


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## klobucarteam (Aug 11, 2009)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

Did you check your fuses? the panel under the steering wheel?


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## germancarnut51 (Mar 23, 2008)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

THE FIRST THING TO DO IS TO GET A AC MANIFOLD GAUGE SET AND A BENTLEY SERVICE MANUAL.
The refrigerant cans with the built-in gauges are WORTHLESS ! ! ! The gauges are so inaccurate that not having a gauge at all would probably be more accurate.
With an ac manifold gauge set you would be able to see the pressure on both sides at the same time, and diagnosing the problem would be much easier. At this point you're taking shots in the dark. How do you know if the ac system has enough refrigerant if you can't see the high pressure circuit refrigerant level?
Are you using a Bentley Manual to follow the electrical circuitry?
The ac temperature cut-off switch on the coolant flange does not affect the cooling fans. It controls the compressor by cutting off power to the ac clutch coil. It's in line with the ambient temperature switch, and the low pressure/cycling switch.


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## jorge r (Apr 27, 2006)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

How much refrigerant have you put in the system, aproximately? Refrigerant comes in 12oz. cans unless there is additives in the cans.
The high side should not be cold, it should be hot, at least 110*F before the expansion valve.


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## redcabriolet89 (Nov 2, 2003)

*Re: 1997 Jetta GL A/C problems???? HELP! (jorge r)*

I talked to a guy at a repair shop today. He wants $250-$300 to fix it just based on the info I gave him, not yet looking at the car. YES, he has the guages!!!! He said it sounds like the expansion valve is open all of the time. What do you guys think???????


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## germancarnut51 (Mar 23, 2008)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

YOU REALLY NEED TO DO SOME READING ABOUT AC SYSTEMS, GET A BENTLEY SERVICE MANUAL FOR YOUR CAR, AND A AC MANIFOLD GAUGE SET.
You could answer all of your own questions that way.
First of all, the Expansion Valve is not a moving part or a gate that opens and closes. It's a metal block with a precisely manufactured hole of a specific size. Liquid refrigerant under pressure goes through the hole at a specific rate and EXPANDS, absorbing heat, and turning into a gas. This is where the name "expansion valve" comes from. The valve does not open and close, it's always open. If someone at a ac shop told you that your ac system has a problem with the expansion valve because it's always open, he was blowing smoke up your ass.
On a MKIII VW, the expansion valve is located on the right side of the firewall. It's the square metal box that is covered by black rubber insulation that the ac hoses from the front of the car are connected to.
To change it, you discharge the ac system refrigerant, and unbolt it. It's that simple.
Now, BUY YOUR OWN AC MANIFOLD GAUGE SET AND BENTLEY MANUAL. A book on auto ac systems would be a good idea as well. Haynes publishes one that is not that bad.


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## bearing01 (May 27, 2004)

*Re: 1997 Jetta GL A/C problems???? HELP! (germancarnut51)*

The Bentley manual will give details of the components of your AC system, and the specified operation of things like the pressure or temperature trigger points of the switches and nominal expected operating pressures. It won't provide theory on how an AC system works. You'll need to buy a book on AC to understand it properly.
The expansion valve is a restrictive orifice, as the last poster said. It's essentially a throttle valve for refrigerant entering the evaporator. It does have a feedback control mechanism. After liquid refrigerant has picked up heat, inside the evaporator, and has vaporized, this vapor exits the evaporator and passes back out through the big side of the expansion valve. The valve senses the temperature of this vapor. That temperature regulates the position of a rod running through the expansion valve, that regulates the opening of the pintle inside the orifice. This adjusts the throttling of the refrigerant into the evaporator to regulate evaporator temperature to prevent it from icing up. So, yes, the evaporator could possible be stuck slightly open more than it should, but I doubt it. If it were you would have low high-side (compressor output) pressures and higher than normal low-side (compressor suction input) pressures. The AC wouldn't work. However, if these are the pressures you are getting then chances are it's not the expansion valve, but rather, it's a bad compressor. The compressor is not a fixed displacement compressor. It is a variable stroke swash plate type compressor. There's a pressure regulator inside the compressor that adjusts the piston stroke and therefore the suction and head pressures generated by the compressor. It has more dominance in regulating pressures than the expansion valve. The compressor's built in regulator is known to go bad on the SD7V16 compressor over time. 
What you want is to fully understand how AC works and how it works with the SD7V16 variable stroke compressor, buy a real AC manifold gauge, and figure it out yourself. That, or bring it to someone who can do it for you. If you own the AC manifold gauge then if you give us your pressures then we can help you figure it out. However, a lot of info may be overlooked troubleshooting this way and our suggestions may cost you money you don't need to spend.


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## bearing01 (May 27, 2004)

*Re: 1997 Jetta GL A/C problems???? HELP! (bearing01)*

Here, this may help.
You got the block type expansion valve, page 26.
http://www.tomorrowstechnician...5.pdf
This may help too
http://www.autofrost.com/autodisc.pdf


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## jorge r (Apr 27, 2006)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

When the expansion valve is stuck wide open, it would have to be a thermal sensing type, a higher volume of refrigerant passes thru the evaporator and may freeze the evaporator solid and the suction line would also show frost and possibly flood the compressor with liquid refrigerant. This is not likely the case.
Our VW has an orifice seperating the high from the low side and the compressor regulates how much refrigerant flows thru the orifice. The volume of refrigerant in the evaporator determines how cold the evaporator gets and the refrigerant pressures according to heat load. 
Do you notice the line after the expansion valve constantly cold? The line going back to the compressor should be cold and sweaty when near fully charged. Do you have nearly 28 oz of refrigerant in it?
Just before the expansion valve, there is a filter, a wire mesh screen, a sock that gets clogged when the system has been contaminated with moisture, air, impurities, a new expansion valve comes with a new sock. If this sock is clogged, the cooling will not work due to lack of refrigerant flow and the high/low pressure readings will indicate a clog.
If _StopLeak_ has been introduced into the a/c system and the system has been exposed to the atmosphere afterwards, _StopLeak_ hardens when exposed to air and may have hardened inside the critical a/c system, Imagine the extend of damage this product can cause.


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## bearing01 (May 27, 2004)

*Re: 1997 Jetta GL A/C problems???? HELP! (jorge r)*


_Quote, originally posted by *jorge r* »_When the expansion valve is stuck wide open, it would have to be a thermal sensing type, a higher volume of refrigerant passes thru the evaporator and may freeze the evaporator solid and the suction line would also show frost and possibly flood the compressor with liquid refrigerant. 


How I understand it, if TXV is stuck wide open and there is no other restriction (like TXV screen is not clogged with debris) then the compressor is pushing refrigerant against less restriction. It's like short circuiting the compressor. Compressor head pressure won't build and if there's any heat in in the refrigerant then that heat won't get dissipated in the condenser. Therefore, not as much refrigerant will be in liquid form when getting back to the evaporator. Therefore the refrigerant will be less capable of picking up heat. Also, if the TXV is wide open then more than normal volume of refrigerant can enter the evaporator. When the compressor inlet sucks refrigerant out of the evaporator it can suck more volume than normal, therefore the compressor doesn't pull down the pressure of the evaporator to the 30psi range, or lower, as it would say if the TXV were operating normally. Because excessive refrigerant can enter the evaporator, but compressor can't reduce the pressure on this refrigerant, that refrigerant won't pick up much heat. The evaporator won't get cold. Because refrigerant isn't picking up heat, and because the compressor can't pressurize it to remove whatever heat is picked up, the low side pressure will be higher than normal (say 60psi, instead of expected 30psi) and high side pressure will be lower than normal (say 120psi, instead of expected 200psi). The evaporator therefore, at 60psi, will be around 60'F and can't cool. It won't ice up.
However, take the opposite scenario where the TXV inlet orifice screen is partially blocked and say the compressor is not a variable displacement type that self regulates its inlet pressure. Say the compressor inlet can suck the low side pressure down to zero psi if it wants. Now, the partially blocked TXV only passes a little refrigerant. The compressor sucks hard on the low side (on the evaporator) and pulls the pressure down below 30psi. The little bit of refrigerant that does get into the evaporator is below 30psi. It will be very cold. It will be below 32'F (0'C) and the inlet of the evaporator will be very cold. Air moisture that condenses will freeze on the inlet of the evaporator. Once the refrigerant picks up this heat, in the process of freezing that moisture, it passes on through the evaporator above 32'F. Incoming air therefore won't be cooled. The refrigerant will gain a lot of superheat (hot vapor just gains in temperature without picking up much heat), which does not pick up much heat energy from incoming air. As time goes by, the ice that builds up on the evaporator coil is an area that becomes insulated with ice. Over time the evaporator will grow ice, from the inlet area, across the coil. Eventually the entire coil will become iced over. All this happens while there appears to be little cooling affect from the AC. While all this happens, because there's only a little bit of heat picked up in the evaporator (because of only a little refrigerant getting past the blockage) the high side won't have to build as much pressure as normal, because it doesn't have much heat to dissipate. More heat picked up means higher high side pressure in order to dissipate more heat. In this blocked TXV case the low side pressure would be maybe 20psi or less and high side pressure would probably only be around 100 to 120psi.
Note, Refrigerant at:
30 psi is at 34'F
60psi is at 62'F
125psi is at 100'F
High side pressure needs to be high enough so high side temperature (125psi = 100'F) is hotter than outside air temperature by around 40'F. That is so heat leaves 100'F area and enters a cooler area. On a 60'F day I would expect high side pressure to be around 125psi. On a 100'F day I would expect high side pressure to be around 230psi or more, so high side refrigerant temperature will be at 140'F. That's just ball park numbers.



_Modified by bearing01 at 4:52 PM 8-13-2009_


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## jorge r (Apr 27, 2006)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*


_Quote, originally posted by *redcabriolet89* »_Tested some things tonight.......







....... refrigerant is at the correct level*(I refilled it with the kit that has the built in gauge, *










































http://****************.com/smile/emthup.gif









*how much refrigerant did you install ??*
A can with a gage doesn't have enough to fill the a/c system, how much did you use??
The expansion valve may get cold, the system may run, but the evaporator will not get thuroughly cold if there is not enough refrigerant charge in the system, and, you may end up paying your a/c technician needlessly.
... how much refrigerant is in the system?


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## redcabriolet89 (Nov 2, 2003)

*Re: 1997 Jetta GL A/C problems???? HELP! (jorge r)*

30oz was installed. One 18oz and one 12oz can. System calls for 26-29oz. It should have plenty.


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## germancarnut51 (Mar 23, 2008)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

It's my experience that most systems need more than the spec. amount before they are working well.
Some is lost when you purge the gauge set and hoses before connecting to the ac system, some is lost when connecting the hoses, and some is lost at the end because it never entered the ac system.
So from my experience, your ac system may not be full. Without an ac manifold gauge set to check the high and low side pressures while the system is operating, there is no way to tell for sure if the correct amount of refrigerant is in the system.


_Modified by germancarnut51 at 12:46 AM 8-15-2009_


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## jorge r (Apr 27, 2006)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

30 ounces should have some cooling effect. The refrigerant cans other than the 12oz size come with 3 or more ounces of other additives, reducing the amount of refrigerant in the can.
I'd guess:
1. The refrigerant has quickly leaked out. 
2. The system has a clog. The condensor discharge would not stay hot after a/c start up and the suction line wouldn't be cold if so. If the filter dryer has clogged or restriction, you would feel a temperature difference between inlet and outlet of filter dryer.
or 3. The compressor quit pumping.


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## redcabriolet89 (Nov 2, 2003)

*Re: 1997 Jetta GL A/C problems???? HELP! (bearing01)*

I got some gauges from my mechanic at work. The low sode is reading 47psi and the high side is reading 90psi. Outside air temp was at 70 deg F. What do you guys think????


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## redcabriolet89 (Nov 2, 2003)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

My neighbor thinks the compressor is bad.


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## germancarnut51 (Mar 23, 2008)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

If you are reading the gauges correctly, and they are accurate, it sounds like the compressor is in fact bad.


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## bearing01 (May 27, 2004)

*Re: 1997 Jetta GL A/C problems???? HELP! (germancarnut51)*

yes, bad compressor.


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## redcabriolet89 (Nov 2, 2003)

*Re: 1997 Jetta GL A/C problems???? HELP! (bearing01)*

Put a used compressor in today. Worked perfectly!!! Thanks to all!!!


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## lewelling (Jul 2, 2007)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

is the fan coming on? does the clutch stay on?


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## redcabriolet89 (Nov 2, 2003)

*Re: 1997 Jetta GL A/C problems???? HELP! (lewelling)*

yep.


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## jorge r (Apr 27, 2006)

*Re: 1997 Jetta GL A/C problems???? HELP! (redcabriolet89)*

Just in time for the rest of the summer.


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