Aircon Charged But Declining Fast

[Barlidge]

Hi everyone I wonder if you can shed some light.

 

When I bought my 2003 TDI just over a year ago the panel flashed indicating no pressure, knowing these cars suffer with the aircon I just resigned myself to it not working and having quite a few other areas of the car to spend money on it went to the back of the queue. However seeing Qwik-fit had an offer on that if they couldnt improve the aircon there was no charge for a regass I figured it was worth a go.

 

Yesterday they spent an hour vaccuming and recharging and straight away to my suprise it kicked in blowing a lovely cold 6 degrees, still a little dubious and suspecting it to leak out I bought a pressure guage from halfords and checked the system there and then, it read a steady 30psi. However, for the rest of the day the air coming out gradually seemed to get warmer and warmer and this morning it seems almost warm again, I have rechecked the pressure in exactly the same circumstances and its fluctuating between 29 - 33 psi. The compressor seems to be running quite happily.

 

What could cause the gradual decline within 24 hours if its not pressure loss and do the small fluctuations have anything to do with it as I dont recall it fluctuating yesterday?

 

As always many thanks for any help.

 

Bruce

[seatkid]

Stop messing about with it! Every time you connect your gauge you lose a bit of gas, if only takes a relatively small amount lost to affect its performance. The pressure varies depending on many things, and you cant measure the amount of gas directly from pressure readings.

 

Because its climate control, it will be trying to maintain a constant temperature unless you set it to LO. Even then I personally find the performance of CC is dependent on external temperature (the hotter outside, the cooler the air) and the fan speed.

 

As long as the compressors working, you have sufficient gas in your system. Just keep it running and see how long it lasts.

Edited June 21, 2011 by seatkid

[Barlidge]

Thanks Seatkid but a little harsh maybe!

 

The first reading was to obtain a reference from which to gauge the speed and amount of any losses from.

 

Both test were carried out after a run at normal operating temperature with the climate set to Lo and at comparable abient temperatures.

 

It lasted less than 24hrs, hence the requirement for the second test to see if the cause was a loss of pressure referring back to my 'just charged' reference point.

 

I realise a pressure test is not the ideal test method but it is all I have available to help investigate before posting for help. I have no previous history of this system ever working so trying to eliminate the most obvious first seems logical. Something has stopped working within 24hrs and I was just looking for advice as to where to look next.

 

Messing about with it? I thought thats what this forum was for, to help us mess about with our gals in a more educated manner!

[Barlidge]

Does the gas convert to liquid in a similar way to other gasses when under pressure? Meaning the pressure gauge will not start decreasing till the final fumes escape the system?

[seatkid]

The compressor compresses the gas and the gas changes state under pressure to liquid - in the process releasing heat.

 

The liquified gas passes through the condenser (mounted in front of the radiator) to cool it to near ambient. It then travels round to the bulkhead and enters the evaporator (mounted in the dash) through an expansion valve (basically just a constriction device).

 

On the other side of the valve is the evaporator which is at low pressure. The liquified gas changes state (boils) back into a gas because of the pressure drop. In the process, due to latent heat of evaporation, the gas cools and voila you have a cold evaporator - which is basically a radiator over which the fan blows air to provide cool air.

 

The gas then travels back to the compressor back via the receiver/dryer which is basically a filter come reservoir.

 

Therefore you have a high pressure (liquid) side and a low pressure (gas) side when the system is working normally.

 

Because of the design of the compressor (a one way device) and expansion valve (a device that needs a minimum amount of pressure to open) the pressure will not necessarily equalise even after the system has been switched off a while (dependent on bypass leakage).

 

Everytime you plug in your gauge, you release some gas (technically this is illegal). If you release just say 10 - 20g of gas each time, you will find the system cooling will start to drop dramatically after several such releases.

[Barlidge]

Thanks Seatkid, that description is very clear and extremely helpful.

 

Are you suggesting that by checking the pressure once straight after the recharge could have caused enough loss to stop the system working? While I take on board your point about the loss incurred I'm not sure that is the cause as the decline was gradual through the rest of the day.

 

The system still appears to be running, no flashing display, compressor running, no strange noises etc but the air coming out is now back to being warm.

 

Are there any other checks that can be done to help diagnose the problem?

 

Thanks again.

[seatkid]

Are you suggesting that by checking the pressure once straight after the recharge could have caused enough loss to stop the system working? While I take on board your point about the loss incurred I'm not sure that is the cause as the decline was gradual through the rest of the day.

 

The system still appears to be running, no flashing display, compressor running, no strange noises etc but the air coming out is now back to being warm.

 

No. a single check shouldnt make much difference - but if its like me when I check the tyres, I always seem to let a fair bit of pressure out in my bungling to get the gauge to fit right.

 

There are a number of possibilities I think.

 

I assume you have a reasonably clean pollen filter i.e. its not completely blocked

 

One is the temperature flap is not driving fully to the lo position - sticking flaps are a known problem but they usually throw up a fault code/flashing display. You can try exercising the flap by changing the temperature from LO to HI ot LO several times - you need to wait about 30 seconds in between each change to wait for the flap to move (it moves slowly)

 

Another is the internal seals in the compressor are ineffective so the compressor isnt pumping effectively. However as it was working well earlier, I dont think it would deteriorate that quickly.

 

Another possibilty is a blockage due to debris etc. This can happen at the expansion valve and also in the receiver dryer.

 

 

I would check the outlet temperature (face vents) with a digital thermometer, using your hand is not very scientific and its easy to think its not doing its job - and dont expect an old system to get down much below about 10 degrees - just be happy with that. Also remember the a/c only works at the front - the rear blower is just a recirc heater and that usually blows warm even when its turned to LO.

 

If your not happy with the temp, then have a word with Kwikfit, they dont charge you if the regas doesnt improve the temperature by 10% (provided it was warmish to start with) - they may agree to regas it at a reduced price if youve recently done it with them. You will they know how much gas precisely was lost and it may also remove any contaminant (water) that may have (but shouldnt have) been left in the system. They also put in another 10ml of oil, which will help the seals swell and may increase its effectiveness.

[Barlidge]

Thanks again but just went out in the car and the display has started flashing, checked it and sure enough its only about 2-3psi, I guess it was leaking all along.

[seatkid]

Sorry to hear about that. Yours being a Mk2 there is a good possibility the leak is at the dryer - see here - Unfortunately the dryer is integrated with the condenser so you have to change both.

 

A specialist with sniffer gear should be able to check/locate the leak - dont trust guys who use dyes.

[chrispb123456]

Sorry to hear about that. Yours being a Mk2 there is a good possibility the leak is at the dryer - see here - Unfortunately the dryer is integrated with the condenser so you have to change both.

 

A specialist with sniffer gear should be able to check/locate the leak - dont trust guys who use dyes.

Hi Seatkid

Could you give your reason(s) for that statement

"dont trust guys who use dyes" as the specialist I know uses both, and seems to be a standard now when having system regassed.

[Barlidge]

Nice link, thanks for that, just been out to have a look, took 5 mins to take of the 4 bolts for the top of the grill, manage to pull away enough to get the cap off and have a look, lots of silvery white crusty deposits.

 

 

Poured in a little water and lo and behold one steady stream of bubbles at least 8 per second and a second intermittant stream a bit slower, bearing in mind the system is almost empty now.

 

So does this mean the condensor/dryer needs replacing or can that cap be sealed?

[chrispb123456]

Whole drier/condenser combined about

[Bigjeeze]

Whole drier/condenser combined about

[Barlidge]

I believe its a choice of the the following parts:

 

Drier only:

Europarts Drier Only

 

Complete Condenser

Europarts Condenser

 

Having now found my TIS CD and the fact that the system has emptied itself it seems feasable to source some new o rings and the correct quantity/spec oil and fit it myself. Has anyone else done this and could there be any problems I havent forseen?

[RADIOTWO]

I believe its a choice of the the following parts:

 

Drier only:

Europarts Drier Only

 

Complete Condenser

Europarts Condenser

 

Having now found my TIS CD and the fact that the system has emptied itself it seems feasable to source some new o rings and the correct quantity/spec oil and fit it myself. Has anyone else done this and could there be any problems I havent forseen?

 

Have you got your own vacuum unit ?

 

Radiotwo

[Barlidge]

No but would that be necessary as the system is empty?

[RADIOTWO]

No but would that be necessary as the system is empty?

 

Course it is ! and it is not empty as you say it has "air" and there will be some damp in there and that's not a good thing.

 

and when there is a vacuum, it will help to pull the weighed gas, and oil in !

 

Radiotwo

[seatkid]

Hi Seatkid

Could you give your reason(s) for that statement

"dont trust guys who use dyes" as the specialist I know uses both, and seems to be a standard now when having system regassed.

What I should have said was "dont trust guys who use just dyes"

 

Firstly I dont think dye is a good thing to have in your system, its just a contaminant that cant be removed once its in.

 

Secondly my experience when the dealer lobbed in 3 lots of dye, it didnt help them find the leak, most posters who've gone this route seem to have a similar experience.

 

You end up paying for something and getting nothing.

[Barlidge]

Granted I did observe air bubbles from the water test, however within 48hrs from recharge the system was down to at 2-3psi which was a couple of hours before the water test, I've still got to obtain replacement parts which will prob run into next week so I was thinking the final residue would have depleted by then.

 

Please excuse some ignorance, I do not claim to be an aircon expert hence the request for advice from you guys here, and am very gratefull for all recieved so far. But I do have good general mechanical and diy expertise (completed C&G Parts 1 & 2 Mechanical Engineering circa 1989) and as many others on here I am on a tight budget so I have to explore any areas where money can be saved by doing work myself.

 

Good call from Bigjeeze, I removed the bumper cover a while ago and had a better look at the condenser, there is a 3" diameter oily resedue near the bottom n/s corner and also an oily residue around the n/s pipe conection flange.

 

If I was to fit myself and then take to a 'dealer' for regass I was working under the impression that prior to filling an aircon machine vacs out the system. Also looking at TIS the residual oil in the condenser/drier would have to be reclaimed and measured and replaced accordingly with the correct grade pag oil during replacement.

 

Please correct me if I'm wrong in my assumptions.

 

Thanks also to seat kid for referring to an excellent earlier post which has yielded masses of good information.

Edited June 22, 2011 by Barlidge

[Barlidge]

A couple of updates:

 

Reading Seatkids latest post reminded me that the guy at Qwik-fit said he had put dye in during the recharge, this also shows on the reciept but there was no indication of any dye around the cap, not sure if thi means anything or not.

 

Also I hopefully have just got a bargain £65 + £10 p&P:

 

Condenser

 

I have spoken to the seller, he confirms it is a genuine ford/motorcraft replacement part, still not sure if I will fit or get someone else to.

Edited June 22, 2011 by Barlidge

[mikej]

Pretty sure you can pick up a condensor inc drier already fitted for approx

[Barlidge]

New condenser all fitted and booked into aircon specialist tommorrow morning (not Qwik fit). To be honest once you have the bumber off, cut away a little fibreglass and follow some simple common sense it was an easy job.

 

1) Confirm system pressure is 0 or have the system evacuated.

2) Remove bumper cover.

3) Remove bumper bar.

4) Cut away fibreglass to allow condenser brackets to pass out the front.

5) Disconnect hose lines and immediately wrap in sandwich bags (or clingfilm etc) to minimise contamination.

6) Unbolt condenser/drier and remove.

7) Install new condenser/drier.

8) Reconnect hose lines; unwrap, wipe clean, lubricate and fit new o rings, tighten.

9) Refit bumper bar and cover.

10 Seek specialist to vac system, pressure test and refill with correct quantities.

 

In removing the old condenser I observed the following:

 

The high pressure side had traces of oil and dye, both inside and outside the o ring but on the drier side there was no trace of oil or dye.

 

I was unable to retrieve any residual oil at all from the condenser/drier.

 

On the reverse side of the oily patch earlier observed in the n/s bottom corner of the condenser there were green crustations indicating the condenser was leaking along with the drier cap and also the high pressure connection.

 

I have deviated from TIS in that I have not added any new oil to the condenser, this is based on 2 things, 1) The recharge equipment has progressed considerably since TIS was written and instead of a couple of gas bottles they can now evacuate, clean and measure. 2) the aircon guy I'm taking to for the recharge assures me there is no need as they will take care of the quantities based on 1) above.

 

I am sure that this will not be the end of my aircon troubles, but if it helps someone else in a similar situation then all good, I will post an update tomorrow after recharge but the true result wont be known until the gas runs out :19:

[derekod]

New condenser all fitted and booked into aircon specialist tommorrow morning (not Qwik fit). To be honest once you have the bumber off, cut away a little fibreglass and follow some simple common sense it was an easy job.

 

1) Confirm system pressure is 0 or have the system evacuated.

2) Remove bumper cover.

3) Remove bumper bar.

4) Cut away fibreglass to allow condenser brackets to pass out the front.

5) Disconnect hose lines and immediately wrap in sandwich bags (or clingfilm etc) to minimise contamination.

6) Unbolt condenser/drier and remove.

7) Install new condenser/drier.

8) Reconnect hose lines; unwrap, wipe clean, lubricate and fit new o rings, tighten.

9) Refit bumper bar and cover.

10 Seek specialist to vac system, pressure test and refill with correct quantities.

 

In removing the old condenser I observed the following:

 

The high pressure side had traces of oil and dye, both inside and outside the o ring but on the drier side there was no trace of oil or dye.

 

I was unable to retrieve any residual oil at all from the condenser/drier.

 

On the reverse side of the oily patch earlier observed in the n/s bottom corner of the condenser there were green crustations indicating the condenser was leaking along with the drier cap and also the high pressure connection.

 

I have deviated from TIS in that I have not added any new oil to the condenser, this is based on 2 things, 1) The recharge equipment has progressed considerably since TIS was written and instead of a couple of gas bottles they can now evacuate, clean and measure. 2) the aircon guy I'm taking to for the recharge assures me there is no need as they will take care of the quantities based on 1) above.

 

I am sure that this will not be the end of my aircon troubles, but if it helps someone else in a similar situation then all good, I will post an update tomorrow after recharge but the true result wont be known until the gas runs out :rolleyes:

Edited June 27, 2011 by derekod

[derekod]

For some reason I could not remove the quote from my reply!

 

Trying a second time

 

I have the same problem with my 2002 Galaxy had it drained and recharged about two years ago and it would not hold the vacum nicely, there was no sign of any dye found anywhere. After a long journety over the weekend it was not blowing cold air any more so I had it vacumed down and recharged again same thing not holding the vacum for long but it did not stop the system from recharging it. Lasted for 3 days then I found the leak at the top of the condenser on the left hand side close to the condenser