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Discussion Starter · #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.
 

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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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🏴󠁧󠁢󠁳󠁣󠁴󠁿X260 R-Sport in Aurora Red
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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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Discussion Starter · #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.
 

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🏴󠁧󠁢󠁳󠁣󠁴󠁿X260 R-Sport in Aurora Red
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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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Discussion Starter · #6 ·
Gav, will try again and engine off showed zero. Think iCarSoft showed clutch engaged. Will try to actually see clutch is working.

Thanks all.
 

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MY 2012 XF S Portfolio Ultimate Black
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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.
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.
 

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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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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.
 

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Found it . . .
 

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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.
 

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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.
 

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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.
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
 

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Discussion Starter · #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.
 

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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.
 

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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.
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.
 

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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.
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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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.
Basically yes. The stop start checks for demand from electrics and temp.
 
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