Question on 2017, L405 air-con. It has been re-gassed twice in the last year, so suspect I may have leak. Guess I need to get some dye injected to confirm that, but….it works fine most of the time, cool air and rear fans working to maintain selected cabin temp. Last few days though, I have noted when car has sat in the sun all day and cabin is red-hot, it takes about an hour before cool air emerges from the vents. It is fine in the morning when exterior temp is lower. If I start journey from my garage, so cabin temp is cool, even if exterior temp is high, also works fine. If I start journey after it’s sat in the sun all day….nothing for a good hour, then gradually vent temp noticeably lower and eventually perfect. Once cabin temp reached, subsequent short journeys, it also works perfectly.
Set to max-aircon, so re-circ selected.
I am wondering where to start? Dye for leak checks certainly, pressure test, but are there any other likely candidates? I don’t want to go near the Derby Dealer, a friend has had good results from Halfrauds with his Audi (correctly diagnosing a cabin sensor fail), but wherever I go, I’d like an idea of where to point them, if there are any common issues on L405.
Thanks in advance. L405 2017 TDV6 AB
Previous toys:
4.4 TDV8 Westminster. Santorini Black
1976 Lightweight
4.0l P38
2 Disco 3s
Lots of Jags. Confirmed JLR nut.

It sounds like low pressure in the refrigerant, but not low enough that the system stops working. Mine blows icy cold within a few seconds of switching on even in this temperature.

The problem with mine was the condenser - it's right at the front and can get damaged by stones. The system was empty, though a pressure test suggested the system held pressure, and the aircon specialist refilled the system. However, we then spotted a tiny area of bubbling on the condenser, but only when the condenser got hot - so we were lucky to find it.

A new condenser and 3 years later still runs at the same temperature.

Find a good independent aircon guy who knows what he's doing. I personally wouldn't use a main dealer or Halfords for something like this. The fix cost me £35 for the initial pressure test, then £225 for the condenser, fitting and re-fill, though I did most of the donkey work removing bumper and all the front end necesary to get to the condenser.

Hi Zebedee,

Yeah, also wondered about Condensor. Thanks for your reply, I’ll get searching for local air-con guy. 👍🏻 L405 2017 TDV6 AB
Previous toys:
4.4 TDV8 Westminster. Santorini Black
1976 Lightweight
4.0l P38
2 Disco 3s
Lots of Jags. Confirmed JLR nut.

Get an A/C, specialist to look at it, they will have the experience and knowledge to carry out correct fault diagnostics. This is where lots of garages fail.

At sea part of my job is looking after hotel sized A/C systems and large fridge / freezer systems with walk in rooms, quite easy to work on, but diagnosing faults can occasionally be the most difficult part of the repair process.

If you have a multi-function OBD tool then you can view the real time HVAC data from compressor on/off, to system pressure, to evaporator temperature and the vent actuators position and the individual vent air temperature. That data will tell you if you have a problem and point you in the right direction to get it sorted.

I really wouldn't start pumping dye in unless you know you are looking for a leak. It is just as likely to be in need of a top off or the mixer door actuator has lost teeth on the drive as it is to be down to a leak.

When I bought my RR in March I didn't know until May that the AC wasn't running cold. It was just a top off needed in my case as the pressures were too low. You expect a 6 year old car to need a top up on the refrigerant gas as a system will lose 2-4% of its charge a year which is normal and to be expected.

Thanks very much for the replies. Found a great Indy who diagnosed a gas leak between the condenser and drier.
It’s still under dealer warranty, so dropped there and in a happy coincidence they confirmed the same diagnosis.
Supply and fit a new condenser, FOC……but the interfacing O rings are on “back order” for up to 2 months! Which makes me think they have no idea when they’ll be in stock! I get that the consumables and hardware will be from different sub-tier suppliers, but how on earth do JLR manage their stock levels, allowing cheap consumables to deplete!
Anyway, partial resolution at least, pending a re-visit to dealer when the O rings arrive!

Thanks for your help. L405 2017 TDV6 AB
Previous toys:
4.4 TDV8 Westminster. Santorini Black
1976 Lightweight
4.0l P38
2 Disco 3s
Lots of Jags. Confirmed JLR nut.