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Air Conditioning Leaks

7K views 61 replies 10 participants last post by  hamedhbb 
#1 ·
A/C sytem had no charge in it, took it in for a recharge. It pulled a vacuum and held it and was then charged. That was in April. Now need a/c and it is not very cold, in fact perhaps not cooling at all.

If anyone has experienced a leak in the a/c system where was it.

The Rover 75 diesel had a design problem in the a/c dept whereby a reinforced rubber coolant pipe ran alongside the aluminium a/c pipe and the rubber pipe would wear a hole in the a/c pipe. However, with the rubber pipe against the hole in the a/c pipe when a vacuum was pulled the rubber pipe sealed the hole so the vacuum test was passed. When the system was pressurised naturally the gas escaped.
 
#2 ·
Do you know that the system has lost its charge again? There are other possible reasons why it's not performing.
 
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#3 ·
Likely your topup was filled with a dye that glows under uv light, I bought a cheap uv light too see if I had a leak. I noticed a trace around where the aluminium pipe joins a rubber hose, but hard to tell how big it is.
i recharged a few months ago and ok still now but it may just be a small leak that took 4 years to get low.
A reputable mobile air con dude can pressure test your system with nitrogen too.
 
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#4 ·
Connected the iCarSoft to the car and ran the engine and the pressure did get up to just over 1,000kPa before I switched the engine off. Unsure whether a dye was put in. The problem with living in cabbage land there are not too many specialists about.
 
#7 ·
That’s not very bad but not ideal as well. It should get to 1500kPa when AC on and 800kPa when AC is off. The AC oil has dye from factory. Just use UV light to find the leak. I found a leakage on low pressure line just next to condenser where a foam traps the road salt there. Easily welded with a blowtorch and low melt rod. Took me 30mins and so far it has held the pressure for about 2months now.

do you see any difference in pressure when switch ac on/off from the climate menu? (Not pushing he fan button) also can read an item called similar to “ac motor current” ? If yes, see if that also changes when you switch ac on and off.

edit: just saw Gav’s message when I posted mine. His figures are probably more accurate.
 
#5 ·
1MPa sounds pretty good tbh I was getting around 750kpa with engine off and peaked at 1.3Mpa with engine on ….can you see if the a/c clutch is engaged with or without icarsoft?
 
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#8 ·
A well known issue with the XF AC is the DPS (direct pressure sensing) valve attached to the compressor. There's a Jaguar Technical Bulletin about it which I'll post (when I find it).
 
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#9 ·
Your pressures as Gav say's are not that bad but Low, 700 engine off 1600 running would be normal.Before you read the pressure make sure the engine is up to temp, otherwise the valve will not open fully due to emission/performance system.
As john just said it looks a bit like the valve, but the system is fairly complex, I bought a set of gauges which give a good idea of the performance of the system without guessing. All of the comments so far are relevant.
 
#12 ·
Paul. I think you should go round with a UV light before you do anything else, start at the front right hand side in front of the radiator, locate the two ali pipes one HP one LP you can follow the HP one up to the top of the nearside wing where the socket is for the gauges.
 
#13 ·
Yes the questions I asked in post #7 is to diagnose dps valve. I took valve out when I repaired mine. Everything was fine. It either works or won’t. It’s a misconception that it could partially work. It’s a simple solenoid valve. So long as car senses a current above 0.5A and LP/HP are within the range it is functional.
 
#15 ·
I actually meant this when I said valve.
A/C Compressor Torque The ATC module transmits refrigerant pressure and A/C compressor current values to the ECM (engine control module) over the medium speed then high speed CAN bus, using the CJB as a gateway. The ECM uses these values to calculate the torque being used to drive the A/C compressor. The ECM compares the calculated value with its allowable value and if necessary forces the ATC module to inhibit the A/C compressor by transmitting the 'ACClutchInhibit' CAN message. This forces the ATC module to reduce the drive current to the A/C compressor solenoid valve, which reduces refrigerant flow. This in turn reduces the torque required to drive the A/C compressor. By reducing the maximum A/C compressor torque, the ECM is able to reduce the load on the engine when it needs to maintain vehicle performance or cooling system integrity
 
#16 ·
FCS interesting. Can I interpret this as if when stationary with cooling on and the stop start is not functioning and I turn off climate control and stop start works that the system knows that the compressor is functioning because the ATC assesses that the compressor is running due to the data it is receiving.
 
#18 ·
This is how I discovered my refrigerant was low, turn off my a/c and my s/s worked everytime.
sounds like you do have a leak albeit small.
a top up would restore your s/s System.
 
#17 ·
I can confirm (well, from what my car does) that the load on the AC system seems to have no influence on the auto start-stop. Even in hot weather when the A/C is working hard, the auto stop will kick in. I have to override it if I want the icy blast to continue.
 
#19 ·
Yes this is the same in the x260 but if it’s particularly warm, the s/s only lasts for a minute as the cabin temp needs cool refrigerant.
 
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#21 · (Edited)
I don’t have s/s on my Jag but in my other car, s/s won’t kick in if the difference between cabin temperature and set point is large.
re valve current, I couldn’t replicate a situation where current was adjusted. It was always zero or max. Workshop manual says however that car uses PWM to change flow-rate. This has conflict with use of thermostatic expansion valve that effectively does the same thing but mechanically.
What is obvious is that you won’t hear AC clutch kick in and out when switching AC on/off. Clutch only disengages when pressure is too low or too high.
For the leakage, check a foam immediately after where ac pipes leaving condenser. Most cars develop a leakage there due to trapped road salt.
 
#22 ·
I don’t have s/s on my Jag but in my other car, s/s won’t kick in if the difference between cabin temperature and set point is large.
. . . . . . . .
Despite what I said in my earlier post, in retrospect I think this is the case in mine also. Been out today with the external temp at 24C and no S/S. Just haven't noticed it before.
When the S/S does cut in when the A/C is running, I get that distinctive wet-evaporator smell for a few seconds.
 
#24 ·
SS is intended to make a difference in situations where the vehicles engine 'could' be stopped from running and therefore producing unnecessary pollutants for the majority of it's journey or part thereof, i.e. journey's in 'grid locked' cities/towns/hamlets where pollution is a health risk, including three places that suffer dangerous levels of pollutants from vehicle emissions I can instantly think of in 'rural' Cornwall ..

"Overall emissions release" is not necessarily the mission objective.



#ignoredagain
 
#25 ·
My Toyota shows some of all times engine was switched off by SS. This can be displayed on the clock that is counted from when car was brand new. Figure is 50hrs which is over 50k miles and over 5years. My estimation is that the 1.3petrol engine it has, uses around 0.5L per hour. That is 25L over 5 years!
I guess this figure will be more for someone driving inside London for instance. Let’s say 4times more! 100lit over 5years?!
 
#26 ·
I'd argue that it wouldn't be so high based on the car requiring to run certain things and retain enough charge to restart itself. In fact is go as far as saying that what it's showing, is pretty much the limit of what can be achieved. It certainly won't be a linear affair.

It's almost certainly a system designed and installed to make the most of, and manipulate the figures given for emissions release to the authorities and sales etc. In the real world, it's a complete waste of time which would probably be reset by the need to replace the battery slightly more often.
 
#34 ·
Glad you have it working again Paul. But as Hamed say's keep an eye on the front A/C pipes. If you can safely get under the car and remove the large plastic tray under the car at the front (loads of screws) you can see in the tray if the pipes are leaking it stands out like a sore thumb, in the tray rigidity sections. If you do find it still leaks figure out which one it is . The HP pipe is a simple fix it fits at the bottom of the condenser, is easy to remove and replace. If it is the LP pipe then you have a problem but it is do-able.
 
#33 ·
I think there's something in the refrigerant that fluoresces under UV light anyway. A bit like semen . . . :oops:
 
#35 ·
Thanks for all the help. Where I took it they state that they do a pressure test using nitrogen and if OK then the vacuum and recharge. Believe they only did the vacuum, which it passed, and the recharge.

Will admit a little relieved that it has been recharged. Of to SW France next Monday and a question of 'would they be able to do the repairs by then if they found a leak' and if not the system would be completely empty.....and temps there can be 40+.

As for looking for any UV staining have just ordered a UV torch.
 
#38 ·
Thanks for all the help. Where I took it they state that they do a pressure test using nitrogen and if OK then the vacuum and recharge. Believe they only did the vacuum, which it passed, and the recharge.

Will admit a little relieved that it has been recharged. Of to SW France next Monday and a question of 'would they be able to do the repairs by then if they found a leak' and if not the system would be completely empty.....and temps there can be 40+.

As for looking for any UV staining have just ordered a UV torch.
If you go to an ac repair shop, they should be able to reclaim the gas, do the repair and regas. If they did a nitrogen test (this is something automatically done if they have state of are machine) then you should be fine. Vacuum test is not enough however.
 
#36 ·
Hopefully you will be fine. These cars without A/C are awful, it spoils the whole experience. The problem with just a vac is that the refrigerant is very searching and at 250 psi it gets where other things can't. My son lives in le sables d'olonne and he say's the temp is over 30 degrees almost every day through the summer.
 
#41 ·
I think there's a couple FMs had this same issue in the same place now.
 
#42 ·
Having my AC topped up on Friday after noticing the icy blast was less so when stationary. I hope it is only this and not the DPS valve issue which I think the extended warranty will cover. Well, it did on my XF.
 
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