Thread: D4 AirCon issues

Originally Posted by terry1738

Good day. Air con started playing up a few years ago wouldn't come on for about 5 minutes gradually got worse and now it works only when it wants to. When its working its great but I would prefer that I control it rather then it decides when to work. Had it looked at and gas was full was told its the compressor but cant be that as it works fine when its decides to work.
Just changed the pollen filter because when I opened the window the air con started to work so thought the change in internal air pressure was causing it (wishful thinking, of course no improvement) so thought maybe temperature sensor. I also saw a land rover notice some valve on the compressor cause an intermittent problem .
What do you guys think , should I go with changing the compressor or maybe find someone who will diagnose the valve which is $50 and I think is accessible from the LHS tyre well or is there something else I can check and replace.
I like to do stuff myself and changed timing belt and manifolds but am a bit stuffed with this one as to what could be causing the problem so any advice appreciated.

It'll be the RCV.

Just about always is.

Originally Posted by shack

It'll be the RCV.

Just about always is.

Sorry, but I really don’t know - what’s an RCV?

Originally Posted by John_D4

Sorry, but I really don’t know - what’s an RCV?

Refrigerant Control Valve.

Essentially a proportioning valve for clutchless compressors.

Originally Posted by shack

Refrigerant Control Valve.

Essentially a proportioning valve for clutchless compressors.

So as it happens, it’s on clutched compressors too, as per LR.

Originally Posted by shack

It'll be the RCV.

Just about always is.

From what I have read you remove the electrical connector, remove the circlip, try to pull it out in one piece, put the new one in and insert the circlip and plug in the connector. I don't know how it works but i assume those holes in the bottom of the RCV twist around to limit the flow of gas through the compressor if so when I remove the valve i am going to lose my gas so i guess you need to close off the gas somehow, if that is right? and if so how do i close off the gas or don't I need to.
I have also read you can do this through the wheel well if you can get the car off the ground and have skinny arms and the patience of Zeus non of which I possess otherwise there is a lot of removal replacement to get down to the compressor.
Is it even remotely possible to do it through the wheel well?
Thanks for the reply and confirming my thoughts that it was the RCV. Terry

Originally Posted by DiscoJeffster

So as it happens, it’s on clutched compressors too, as per LR.

As far as I'm aware the compressors on all D3 and D4 variants are clutchless.

They use an RCV to control output/ compressor output - variable displacement.

Where the confusion possibly arises is they they also all have a "safety clutch".

This doesn't operate like the old school clutched compressors though.

I believe once the safety clutch has been brought into play.. It's cooked.

I think on sanden units the "clutch" is non replaceable.

But I stand to be corrected.

Originally Posted by terry1738

From what I have read you remove the electrical connector, remove the circlip, try to pull it out in one piece, put the new one in and insert the circlip and plug in the connector. I don't know how it works but i assume those holes in the bottom of the RCV twist around to limit the flow of gas through the compressor if so when I remove the valve i am going to lose my gas so i guess you need to close off the gas somehow, if that is right? and if so how do i close off the gas or don't I need to.
I have also read you can do this through the wheel well if you can get the car off the ground and have skinny arms and the patience of Zeus non of which I possess otherwise there is a lot of removal replacement to get down to the compressor.
Is it even remotely possible to do it through the wheel well?
Thanks for the reply and confirming my thoughts that it was the RCV. Terry

It is under gas pressure so you will lose the gas so legally you need to get the gas recovered by a certified AC technician. The system will then need to be pressurised with nitrogen preferably which will help you to get the valve out. You will then change the valve and need to get the system regassed. After that you might see improvement, or not, depending on the health of the compressor.

Originally Posted by shack

As far as I'm aware the compressors on all D3 and D4 variants are clutchless.

....

But I stand to be corrected.

That's a hill I was prepared to die on, but the compressor on the 3L has a clutch in addition to being variable. The 2.7L does not have an electromagnetic clutch.