2017 5.0l SC. 160k km.

Air con is working I would say at 10% of what it used to be in this hot weather. Can sometimes sense some cold air is coming out but it's mostly the warm ambient air even when set to 16c. Even when set at my regular 20c the fans are blowing quite aggressively with ambient air so I assume the car is registering the correct internal cabin temperature and trying to cool the cabin down as fast as it can but to no avail. Seems to be the same from front and rear vents, left and right.

Had the gas checked with the pressure vacuuming and refilling machine in a local AC gas place and it was at 965g so topped up to 1100g. It didnt make any difference.

The pipes under the bonnet where the 2 connection points are do start to get cooler than the ambient temp but not exactly very cold.

Gap iid tool not showing any fault codes.

Are there any simple things I can check at home that might be causing it? Or visit to my local JLR specialist to fix? Should I be expecting to budget for a new compressor or worse?


thanks

take this panel off and clean the sensor behind where the arrow points to....this gets 'fluffed' up and could be the cause..

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Y. O. L. O.
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thank Stan. It was indeed covered in fluff but unfortunately didnt rectify the problem. Still blowing ambient air into the cabin.

I did some live readings from Gap. not sure if indicates anything?

Click image to enlarge

Can you hear the compressor engaging ? 2016 AB SDV8 Barolo black

I think so. if I leave the car idling with the A/C button turned off and then switch the A/C on I hear a click noise coming from the compressors direction.

The vent fans then speed up but with the same ambient air blowing out.

Also engine idle speed stays constant (around 625 RPM from looking at the dial) and doesn't surge up when switching on the A/C and hearing the click noise (even when internal cabin temp is showing 35c and a/c set to 17c)

The L405 has sensors all over for the AC system so you need to get hold of a live data stream scan tool. That will help you quickly find out if you have a system or mechanical fault. You'll be able to see:

Compressor speed (rpm)
Evaporator temperature (C)
Blend door positions (both L + R sides)
System pressures (kpa)

These will show you if the compressor is engaging properly, if it is running properly to deliver the correct pressures and temperatures in the system. The blend door position will let you know that your actuators on air flow are working properly, corresponding with dial setting.

For the pressures you should have you need to look up pressure charts for R1234yf, they are online. Then just check the figures against the prevailing ambient temperatures for the time of reading.

PS - The pressure reading you have is OK for a system working in around 23C ambient.

thanks baz000000. I couldn't find those specific values in Gap (ive sent them a message for validation) but found these.

From what you said and what I recorded and compared to online then the pressure is low vs the ambient temp.

Is this faulty compressor or a leak somewhere?

That second psi pressure is much lower than your original kpa reading, so the second reading was taken at a lower ambient temperature condition or it would appear that you have a leak in the system. The high evaporator temperature is indicative or low charge or a failing compressor. It would be useful to check the compressor running speed to ensure the clutch is operating properly but you don't seem to have access to that data.

To be running at half the 'normal' pressure you would expect to have either lost around a third of the charge or have a very tired compressor. Other less common causes can be a restriction due to breakdown of the drier desiccant partially blocking the capillary/expansion valve or a kinked pipe/compressed hose.

Im not sure how much lower the ambient temp would have been on that reading. its possible as the first reading 2 cars had arrived into the garage 1 hour prior and the doors were closed up until the reading. Since then ive left the doors open for later readings.

This is the last record from gap 10 mins after I switched off the engine (car is on CTEK). Psi is similar even when not under drive from the compressor?

I also enabled air intake pollution. not sure if relevant. it kinda flickered on and off at the start and then stayed not detected since.

Hi

I had a problem like this a few years ago (not on my RR) and after trying everything I could someone suggested that I check to see if the A/C drain tube was blocked. I cleaned it out and the A/C went back to normal..

Worth checking?

Jim

just to close out the thread.

My local indie diagnosed a faulty compressor and replaced it. system working back as normal now.

Any idea on location of ac drain pipe please?