Air condition too cold to the point of no air flow

[oilhammer]

Your compressor is not supposed to "cycle on and off".

 

[alex_tdi]

Your compressor is not supposed to "cycle on and off".

Maybe I'm using the wrong terminology. I just know that the vibration comes and goes, intermittently, when the A/C is on. This started happening right after I got the compressor and dryer replaced. The expansion valve was replaced before when we thought the expansion valve was broken, but later turned out that the compressor itself was busted.

 

[oilhammer]

Look, you came here asking for help. I asked ONE QUESTION that could very well be the reason for your troubles. It never got answered, even amongst the accusations of being a racist.

I am a professional auto tech, I specialize in Volkswagens, and do plenty of A/C work. I can help you, if you help me. We are on page 3 of this thread....

 

[oilhammer]

Do yourself a favor: your Volkswagen was equipped from the factory with a Sanden compressor, a Parker drier, and usually either a Valeo or Hella expansion valve. If any one of those pieces is NOT the above mentioned brands, replace it with one that is. Your local dealer of course can get all the correct stuff, but many aftermarket places can also get the proper stuff. Then, once Volkswagen parts are installed, your Volkswagen's A/C system will once again function they way it is supposed to.

So I will ask one more time.

 

[alex_tdi]

I appreciate the help and I'm not calling you a racist.

As I stated yesterday, I will go to my mechanic and ask for the make of the replacement parts.

However, since I only have a chance to see him on the weekends, I won't know until this weekend.

 

[16vjohn]

Everyone, please let's just drop the whole "Chinese" part and "Chinese" race back and forth posts. I am of Chinese ancestry and I have no problem using any part, made in any country, made by any people, as long as it performs up to spec. If the parts that were installed were inferior, let's just call it that and leave people/nation/race out of it.

Case in point: my Golf was designed in Germany, assembled in Brazil, and uses parts from all over the VW supply chain in Europe.

Has this car had its troubles? Yes. Do I sometimes think VW parts fail prematurely (window falling (cheap plastic retainer clip), fuel pump replacements, failed 01M transmission, LCA, drive axel, water pump, thermostat, etc.)? Yes.

Am I going to start blaming bad German design, bad Brazilian assembly, poor quality Spanish parts, etc.? No.

I have a problem with my A/C. Can we please just focus on the problem at hand?

Thanks.

Alex

Agreed 100%. That is ALL I am trying to say. For some reason these idiots don't see that.

 

[40X40]

Are you for real, dude? Could you be any more insensitive or racist? HOLY CRAP!!!
<deleted>

Agreed 100%. That is ALL I am trying to say. For some reason these idiots don't see that.

The IDIOT in question has been properly and publicly identified.

Bill

 

[oilhammer]

Pwnage!!!! :d:d:d

 

[IndigoBlueWagon]

FWIW, Sanden products for many VWs are now manufactured in China. Like so many multinational companies, they are going where production costs are lower. A lot of cooling and A/C system component manufacturing seems to be moving there.

Country of origin for replacement products is an ongoing discussion between me and our suppliers. And it's naive to think that you can continue to maintain any car without products that come from China. It's also inaccurate to think that all products from China are inferior. More than a few companies are able to maintain quality standards while producing in China. IMHO, it's a matter of being careful about what you purchase. Always been true to some extent, regardless of where something's made.

 

[40X40]

Both 'Chinaloy' and 'Apple' type products are made in China (a country).

'Chinaloy' denotes an obviously inferior and unsuitable product, what ever it may be.

A 'Chinaloy' product could be made somewhere else and still be called 'Chinaloy' because it denotes more the quality of the product than its' origin. There have been some 'Chinaloy' downpipes and turbos come out of Utah, for instance.....

The key difference is quality control, all the way from raw materials to the final inspection.

Bill

 

[DanG144]

Peter,
I agree completely.
The problem is the end user cannot tell in advance, typically.
Sometimes you can do some homework and find the IEEE standards used.
But the easiest way for us to deal with the issue is to go through a vendor that we can trust.
Even the best of vendors can be impacted by poor goods; about the best that they can do is to immediately quit selling the poor products (despite the attractive profit margins); this is why I buy from you and the other trusted vendors when I can.

When I do not buy from a trusted vendor, I am taking the responsibility for the gamble on quality - and it must be a gamble that I can afford to lose.

 

[Bug-n-u]

alex_tdi,

I don't mean to get off the "where are the parts from" subject but I am more interested in what is causing your vibration from seeing your video.

Have you looked under the hood at your serp. belt and your A/C pulley to see what my be causing the vibration when it begans to cycle? Maybe the pulley is loose and starts to wobble, let us know.

 

[alex_tdi]

alex_tdi,

I don't mean to get off the "where are the parts from" subject but I am more interested in what is causing your vibration from seeing your video.

Have you looked under the hood at your serp. belt and your A/C pulley to see what my be causing the vibration when it begans to cycle? Maybe the pulley is loose and starts to wobble, let us know.

Good idea. I will craw under the car later tonight and see if the pullet is loose.

Thanks.

Alex

 

[VeeDubTDI]

http://www.youtube.com/watch?v=gMA5VVHh8xo

Very interesting noise it's making in that video. Sounds serious but I have no idea what it could be.

 

[alex_tdi]

I have noticed a pattern to the noise recently.

Whenever I turn on the A/C in the morning on the way to work when the ambient temperature is low, I never get the noise/vibration. The noise/vibration also doesn't appear at night when it's cold outside.

However, during lunch time, on warm days (around 78 degrees), the noise come on and get louder as the temperature rises.

Do you guys think there is some type of sensor that is perhaps malfunctioning?

 

[Shouse]

I can't wait to see how this plays out ^^^

Oilhammer is a great person and has contributed more to this automotive community than about any other single person on this site.

If you are offended by his comments, too bad for you. How dare you try to be the PC police here. Last I checked 16VJohn, you are not a moderator here.

If anyone is offended by Oilhammers comments here, just overlook them and value the mechanical advise he provides. If you are offended by what you read from him, spend about 30 minutes in southern Mississippi and see how African Americans (sorry, was I just racist ?) are treated and what they are called on the street.

If you think his comments are racist you need a reality check. He is talking about inferior quality parts, not people. If you find Chinese made parts acceptable for your car, feel free to buy your parts from the lowest priced vendor you find on Ebay.

Grow up or go away.

DING DING DING! We have a winner!

 

[manual_tranny]

Wow, lots of blood in the water in here! ^^

 

[Bran Diezel]

i don't think anyone mentioned that a restriction can cause this. It will usually freeze in the location of the restriction. Did they install a filter after the new compressor on the high side? You could have a restriction in the evaporator itself because 40 is a normal reading for the lowside (if the fitting is before the evaporator). 100 Sounds really low for the high side. You may try flushing the system or giving it a little more charge first to see what happens.

 

[Richptl]

OK, so I went to the mechanic today and we confirmed that the air coming out of the vent was below freezing! (-1.2 degrees C). The plan was then to adjust the freon (R-134) in the system.

The first time he hooked up the car to the machine that he uses to charge / discharge the A/C, the pressure was reading around 40 psi on low and about 100 psi on high I think. He was going to recharge the system, but he said that he freon might have frozen up so we turned off the engine and let it sit for a bit. After about 10 minutes, he reconnected the machine to the car and there was no pressure reading at all.

After trying a few times he looked at the line valve (both the high and low) and he said that the rubber inside the valve was bulging out so they had to be replaced. A quick call to the dealer revealed they were $43 each! He said that the American and Japanese cars uses a metal pin style valve that he has plenty of, but he doesn't have any for VWs so he has to special order from the dealer.

So now I'm looking at spending another $100 bucks on two line valves that really don't get used much, so I don't understand how they could fail so easily.

Is this simply a case where the mechanic is not familiar with how VW parts look like? We don't have another VW to compare it against for reference.

Do you guys think I can use the other style valves? A/C has been around for so long, I find it hard to believe these parts aren't standardized yet. Or do you think they be fixed somehow?

Thanks.

Alex

Here are the parts in question (low side valve = 13, high side valve = 12):

An undercharged system will result in an icing evaporator quite often due to uneven refrigerant distribution, BUT THE OVERALL COOLING PERFORMANCE IS LESS. So if you start the AC up with proper airflow and a clean air filter, and right off the air temperature is below freezing, then it sounds as if the compressor is overcooling. Someone else here talked about variable displacement being a need for this car.

As someone else also said, undercharging causes the evaporator to ice in one spot and then the ice creeps until it blocks the airflow off, and you quickly then choke airflow and ice all over. But the overall leaving air temperature on an undercharged system will be higher. You lose performance from undercharging.

If right off the bat the air temp is under 30 deg F, there is more going on here than an undercharged system.

Bottom line is this mechanic does not know AC theory very well. If the air temp is that cold, I would be looking at things other than charge. Is airflow really at spec? Is the compressor oversized? R-134a is at 27.8 psig at 32 deg F. Typically you can run at +28 deg F evap temp before the fins actually start to hit 32 and ice, which is 24.5 psig. If he is reading 40 psig that is over 44 deg F and no way should the evaporator be icing.

You need to take your car to someone else for a 2nd opinion.

 

[Richptl]

This AC system is a beast, 7kW compressor with a maximum CoP of 2.2 means it is a 4 ton unit. That is enough refrigeration to cool a 2400 square foot house in the SW USA. It needs the variable displacement compressor, the proper receiver-dryer and the electronic controls/sensors to operate properly.

Replace the compressor with a fixed displacement compressor in the 150 cc/rev range and it will ice the evaporator. Plus the pressure limit switch will cycle the compressor, causing idle issues. IIRC, the stock specification Sanden compressor has a variation of 10:1 with a max displacement of ~160 cc.

I don't see any issues with knocking inferior Chinese goods. After WWII, Japan adopted the Deming Model, turning their industries into wold class operations. That Sanden compressor? Japanese design at the least.

This poster sounds like he may have hit the problem. If the airflow is at spec and the air is that cold right away, then the compressor is overcooling. Overcharging does not cause overcooling, that is a myth. Overcharging drives up the condensing pressure on TXV regulated systems, lowering efficiency. On a cap tube AC unit, over-charging can squeeze a tiny bit more cooling, but the bigger concern then is "floodback" where liquid can get into the compressor and destroy it.

I am an amateur on cars, but I have 25 years experience in the HVAC business. I work on AC units that put out hundreds of Tons of cooling. Car AC systems are really quite simple.

 

[Richptl]

Oh and 7 Kw with Cop (coefficient of performance) of 2.2 does not necessarily mean 4 Ton. I would expect that the 7 Kw is actually the cooling capacity, not the power input. So divide, not multiply. That would mean that the rating of 7 Kw is 2 Tons (1 Ton = 12,000 BTU/hr and 1 Kw is 3,413 BTU/hr) and it takes 3.2 Kw of shaft power, or 4.3 Hp (1 Hp = 0.746 Kw) to run the compressor. Take into account belt drive losses, which can be quite a bit, and you see how much power it takes from the engine to run AC.

 

[alex_tdi]

Hi Everyone,

It turns out it was just a bad compressor. My mechanic was cool and replaced the compressor and replaced the h/l valve stems free of charge. He also didn't charge me for the A/C recovery and recharge.

I asked him about the make of the compressor, but he said some name I didn't recognize. He just said that he ordered one specifically for my make and since it comes with a 1 year warranty parts and labor, I'm going to trust him... everything else he's worked on for me has worked flawlessly.

I don't expect this compressor to last me another 10 years, but then again, I will probably sell this car before then, so I'm satisfied

Alex

 

[Stone14]

Your compressor is not supposed to "cycle on and off".

Hi Oilhammer.. Sorry I am digging up this old post.. I got my A/C compressor reconditionned.. I just wanted to confirm: The compressor is not supposed to cut off if the evaporator temperature drop? Let's say around 4-5 degrees?

The problem I am having is that my evaporator is freezing up and blocking the air at some time

 

[U4ick]

Hi Oilhammer.. Sorry I am digging up this old post.. I got my A/C compressor reconditionned.. I just wanted to confirm: The compressor is not supposed to cut off if the evaporator temperature drop? Let's say around 4-5 degrees?

The problem I am having is that my evaporator is freezing up and blocking the air at some time

Hello Stone 14,

Just some friendly advice, read and study the sticky on this forum about radiator fan operation and A/C troubleshooting from DanG144 before going any further.......and thank you for bringing up this old post....... I was bored and needed a bit of high entertainment this Sunday afternoon!

 

[BamaB4S]

Huh? Can you remind me where I said anything about all Asians being from China or Japan? ... or Mexicans, Latinos, Vietnamese or Koreans? I'm really trying to figure out what kind of point you're trying to make here besides proving to me how useless you really are. Who is it that needs to get a life here? You've added nothing to this thread but offend me and tell the OP that the parts he just bought should be immediately removed and replaced with OEM without knowing one single fact about them other than the evap is freezing over... Just exactly how much are you trying to take away from this thread? I'm trying to help and you are really just a parasitic drain. It's incredible how long they have allowed your incoherent ramblings to go on. Wow, just wow.

All I'm getting from this is that some folks are easily offended by facts.

 

[J_dude]

Had to go back and read the whole thread after I saw U4ick’s comment above and wow, just wow .

 

[Gothmolly]

"chinesium" is a generic term.

 

[csstevej]

Yeah…..there’s a lot of snowflakes out there…….

 

[Stone14]

Hello Stone 14,

Just some friendly advice, read and study the sticky on this forum about radiator fan operation and A/C troubleshooting from DanG144 before going any further.......and thank you for bringing up this old post....... I was bored and needed a bit of high entertainment this Sunday afternoon!

Good advice.. Will do some more research then

 

[jokila]

Hi Oilhammer.. Sorry I am digging up this old post.. I got my A/C compressor reconditionned.. I just wanted to confirm: The compressor is not supposed to cut off if the evaporator temperature drop? Let's say around 4-5 degrees?

The problem I am having is that my evaporator is freezing up and blocking the air at some time

As he said, it does NOT cycle off and on. It's always on, but the compressor uses a RCV - refrigerant control valve, to regulate the compressor in producing the correct freon flow;. I am pretty sure the RCV uses the fan setting to modulate this.