Air Con Gas Leak

[AUGalaxy]

Hi everyone,

 

I have Galaxy 2004, tdi, auto, 115 ps, dual air con zone system. Last year we topped in the gas in the system. For nine months everything was o.k. Then a/c stopped working. Mechanic said the system needs to be topped up. He did it and three hours later the whole gas leaked out. We realized there was a massive leak out of the condenser. I live in Australia and parts for Galaxy have to be ordered from overseas. I was waiting for few weeks for condenser to arrive. It was installed. When the mechanic started filling up the gas, another huge leak showed up. Compressor was faulty. I ordered new compressor. It arrived after four weeks. Mechanic installed it and realized (during filing the gas) the pressure in the system is to high. I was told the tx valve (the expansion valve I believe; just behind the fire wall) is faulty. He put just 500gr of gas till I get the new valve (thete is a plate which tells just above 1l is normal). No leaks at that stage. It worked fine for three days and then stopped. The gas leaked again I presume as there is not pressure in the system. We did not smell the gas in cabin.

 

Is it possible there is a leak in the evaporator which is in dash or some other place? Pipes seem fine. I just don't know what to do anymore. I did a nice research on this forum, spent a lots of money and the problem is still here. This becomes frustrating. My wife drives our kids in this car and hot Australian summer comes...

 

Many thanks for help!

Mick

Edited September 30, 2012 by AUGalaxy

[chrispb123456]

Expansion valve and evaporator faults are not so common, majority of leaks come from condenser/drier and pipework.

Look carefully at the pipes where they pass through the wheel arch and chassis member, look at where the pipes are clipped they have a habit of corroding in or around the pipe clip.

It's usual to pressure test the system with nitrogen as keep losing gas is expensive, then vacuum the system, if these show no leaks then refill with gas and oil.

Did you use a dye leak detector as this shows up as a green liquid where a leak is suspected.

 

Do you have rear roof vents as some people confuse the rear heater with rear aircon and then overfill the system.

[AUGalaxy]

Expansion valve and evaporator faults are not so common, majority of leaks come from condenser/drier and pipework.

Look carefully at the pipes where they pass through the wheel arch and chassis member, look at where the pipes are clipped they have a habit of corroding in or around the pipe clip.

It's usual to pressure test the system with nitrogen as keep losing gas is expensive, then vacuum the system, if these show no leaks then refill with gas and oil.

Did you use a dye leak detector as this shows up as a green liquid where a leak is suspected.

 

Do you have rear roof vents as some people confuse the rear heater with rear aircon and then overfill the system.

 

 

 

Thanks a lot for your answer! We used a dye leak detector. Will let know mechanic to check pipes again. There are rear roof vents.

[AUGalaxy]

I am just wondering what could cause high pressure in the system apart of the valve? Also, we used the green light test to check pipes several days ago. They seemed fine. We will check them again as I said before.

 

Is there anything else which I should check?

[SilverBeast]

Hi, The leak in the pipework Chris refers to is what I had on my MKII. The aircon specialist I used said the failure was common here and, also also one in the LH rear wheel arch where the pipes for the rear air con enter the cabin.

 

My failure was under the fibre glass panel below the RH headlight, that also goes across the front of the car.

Under the black to the Left of the alternator (though obviously lower down) in this shot.

Here with the camera held low down. It's the smaller high pressure pipe and failed where the clip is. It's not visible with the naked eye (unless using mirrors and lights and several pairs of hands). TIP: If you use a compact digital camera with a flash and know roughly were to point it, you can photgraph hidden parts you can't see, and then zoom in to see more detail than you could with your eyes anyway.

Here it is with the fibre glass panel removed (Remove, bumper, lights, bonnet release, unbolt and support various radiators etc - didn't need to break into any ciruits apart from air con)

where the pipe comes from behind the bumper. The switch on the pipework is I believe the Hi/Lo pressure switch. The pipework is bent out of place where the garage who replaced the radiator left it, probably stressing the joint where it was weakened anyway!

After fixing

and from below, with pipe clipped into correct place

Here's a picture before I removed the panel. The ropes were what I hung the radiators from so we could run the engine/system to check it out. Unfortunately I forgot to take one with it off (grrr!)

 

We could here my leak hissing when we pressurised the system with nitrogen.

Another common point for leaks is under the plastic cap where the drier is fitted (sloping bit at the top of the black plastic tube to the left of the air con condensing radiator(?) in the last shot). I assume this was replaced when you had your condensor replaced - it may even have been where your original leak was as the cap underneath corrodes and the drier can't then be replaced. I was lucky and mine had been greased so we could replaced the drier.

[AUGalaxy]

Hi, The leak in the pipework Chris refers to is what I had on my MKII. The aircon specialist I used said the failure was common here and, also also one in the LH rear wheel arch where the pipes for the rear air con enter the cabin.

 

My failure was under the fibre glass panel below the RH headlight, that also goes across the front of the car.

Under the black to the Left of the alternator (though obviously lower down) in this shot.

Here with the camera held low down. It's the smaller high pressure pipe and failed where the clip is. It's not visible with the naked eye (unless using mirrors and lights and several pairs of hands). TIP: If you use a compact digital camera with a flash and know roughly were to point it, you can photgraph hidden parts you can't see, and then zoom in to see more detail than you could with your eyes anyway.

Here it is with the fibre glass panel removed (Remove, bumper, lights, bonnet release, unbolt and support various radiators etc - didn't need to break into any ciruits apart from air con)

where the pipe comes from behind the bumper. The switch on the pipework is I believe the Hi/Lo pressure switch. The pipework is bent out of place where the garage who replaced the radiator left it, probably stressing the joint where it was weakened anyway!

After fixing

and from below, with pipe clipped into correct place

Here's a picture before I removed the panel. The ropes were what I hung the radiators from so we could run the engine/system to check it out. Unfortunately I forgot to take one with it off (grrr!)

 

We could here my leak hissing when we pressurised the system with nitrogen.

Another common point for leaks is under the plastic cap where the drier is fitted (sloping bit at the top of the black plastic tube to the left of the air con condensing radiator(?) in the last shot). I assume this was replaced when you had your condensor replaced - it may even have been where your original leak was as the cap underneath corrodes and the drier can't then be replaced. I was lucky and mine had been greased so we could replaced the drier.

 

 

Thanks a lot for such a detailed answer. I will be back in Brisbane in few days. As soon as I arrive, will drop of the car at mechanic's place to check the pipes. I will inform you how it went. Thanks again!

[AUGalaxy]

Just an update,

 

A mechanic checked today if there are some leaks in pipes. He could not identify any leak so far. He put also dye to see what is happening. The pressure in the system was to high. He was able to fill just 400 gr of gas. He is pretty sure the expansion valve needs to be replaced, but can`t figure it out where is the leak. One strange thing. I feel (even with 400 gr of gas in the system) cooling was alright for some time. After few hours it getting warmer and warmer. Fans (which cool condenser in the engine bay) are not working all the time and condenser is very hot after 4 min. of running the car. Strong smell of air con gas can be felt in a cabin now. And front vents blow warmer air than rear roof vents. What could be the cause of this? I am coming back to mechanic in two days to see if dye will be shown somewhere...

[seatkid]

If you have rear roof vents then you have a proper dual a/c system. Unfortunately this also means you have two evaporators and two expansion valves (which are bolted on the incoming sides of the evaporators). When you had the condensor changed, and also when you had the compressor changed, it is necessary to flush the system out thoroughly as debris will travel to the expansion valves and block them - the expansion valves are basically small restrictors similar size to a carburetor jet.

 

Whenever the a/c is turned on, the radiator fans should spin constantly at least half speed, even if the compressor kicks out so long as the a/c panel is in auto the fans should be on. You must have a fault here, no fans allow the condensor temperature to rise too much and this will cause a big increase in system pressure. The radiator fans should be on all the time the a/c is set to auto - even if you have no gas in the system.

 

A/c gas is odourless - the smell must be something else - a possible candidate is the compressor clutch - if the pressure builds too high because of a fault, the compressor may be struggling and the clutch slipping/burning. The high/low pressure switch in the system is on the low pressure return side of the compressor, and it may not see this excessive build of pressure because of the fault.

[AUGalaxy]

If you have rear roof vents then you have a proper dual a/c system. Unfortunately this also means you have two evaporators and two expansion valves (which are bolted on the incoming sides of the evaporators). When you had the condensor changed, and also when you had the compressor changed, it is necessary to flush the system out thoroughly as debris will travel to the expansion valves and block them - the expansion valves are basically small restrictors similar size to a carburetor jet.

 

Whenever the a/c is turned on, the radiator fans should spin constantly at least half speed, even if the compressor kicks out so long as the a/c panel is in auto the fans should be on. You must have a fault here, no fans allow the condensor temperature to rise too much and this will cause a big increase in system pressure. The radiator fans should be on all the time the a/c is set to auto - even if you have no gas in the system.

 

A/c gas is odourless - the smell must be something else - a possible candidate is the compressor clutch - if the pressure builds too high because of a fault, the compressor may be struggling and the clutch slipping/burning. The high/low pressure switch in the system is on the low pressure return side of the compressor, and it may not see this excessive build of pressure because of the fault.

 

 

Thanks,

 

The system was flushed after we installed the condenser and the compressor. So faulty fans could cause high pressure in the system. Maybe that is the reason of a faulty compressor we had to change. Maybe we should check high/low pressure switch as well? I am still wondering where is the leak? I presume even tough the pressure is high the gas should not leak... It looks like two independent problems, or maybe I`m wrong. I`m just hoping the evaporators are ok.

[seatkid]

The common area for MKII leaks is the dryer which I think is integrated in to the condensor. I think the tech FAQs show a picture of how to check this leaks (it is hidden on a plastic cap - thats why people miss it on dye.

[AUGalaxy]

The common area for MKII leaks is the dryer which I think is integrated in to the condensor. I think the tech FAQs show a picture of how to check this leaks (it is hidden on a plastic cap - thats why people miss it on dye.

 

Thanks!

 

The dryer is integrated in to the condenser. We installed a brand new condenser and believe it should not leak there. I don`t know. I am going to a mechanic tomorrow again and will see what is the situation...

[AUGalaxy]

Just an update. We found the leak finaly. It is in the rear expansion valve (the rear evaporator is located just above left hand rear wheel). Could anyone tell me if the front expansion valve is identical to the rear one, or they are two different parts? I think I`ve got the part number of the front expansion valve (VW part number7M0820679A or Ford 1564136). Does anyone know the part number of the rear expansion valve? I have to order these two parts as well as the hi/lo pressure switch and to organize shipment to Australia. Is there any other switch (like temperature switch) in the a/c system?

[seatkid]

http://www.auto-parts.spb.ru/cat/au/au.mycat?SelPg&t=3UxhPhdMYT5PTGE_nxYJB_wNOBiOFYf8V2BhPu8T4Q7dTGNBPW5lMt16JybdbGG30B9V5H6Yk3hdVmxxz1bA28PtwfyMB4V/TcQk1L4xxv5uGsowLSEnF_BZxTjefEkEeFy9DJ/9FpRsnHUkT1GMVqWRZm2cP0UX9/6510u3PAL0K1i3GDHwiBWkHyVVr_BfLRKBwPOo6058bay7yRQ= shows the expansion valve on rear evporator as part no 7M0 820 679 A

[AUGalaxy]

http://www.auto-part...POo6058bay7yRQ= shows the expansion valve on rear evporator as part no 7M0 820 679 A

Thanks!

[AUGalaxy]

An update. Both expansion valves have been changed. Pressure switch is changed now (including the pipe where it mounts). We changed so far: 1. Condenser (brand new part); 2. Compressor (brand new part); 3. Expansion valve front (brand new part); 4. Expansion valve rear (brand new part); 5. Pressure switch (brand new part); 6. The pipe where pressure switch is mounted to (brand new part).

I hoped now everything will work properly. The system was flushed. However, the pressure in the system is still to high. Technician was able to put just 500 gr of gas (1000 gr is normal). There are two fans. One is on all the time. The other one is not working. Is this one supposed to be on all the time as well?

There is a cold air in the cabin, but I`m concern the pressure will built up and will leak somewhere again (the reason we changed condenser, compressor and rear expansion valve was huge leaks).

Any thoughts as this becomes frustrating.