Management are happy to carry out the repair - PM me for details of how to book it in, also let me know if you want to supply the parts (pipes & coolant) or you want us to do it. Clearly parts availability from JLR will determine dates.
 
... Unless of course it is item 1 above that is leaking... it does cross over the rear subframe but I've changed several, there is no need to completely remove the rear subframe, just the exhaust, OS front to rear under panel and lower the subframe rear on transmission jacks. Usually takes about 4.5 hours including coolant refill & bleeding.
The other possibility is to just blank off the two pipes that go to the rear if you're not worried about separate rear heating, the vent in the rear of the centre console will still operate, just the ones in the headlining over the rear doors and the ones at the side of the seats won't. You can turn off the rear heating to prevent it blowing cold air on the front screen climate settings, and of course, the rear aircon will still function if you turn it back on for summer.
Graculus thanks for sharing your valuable knowlegde on this subject! I and have a quick question as I’m looking to possibly blank off or bypass these pipes in the short term due to 2 separate leaks in the alloy pipes.
Forgive my ignorance but being feed and return pipes, does the hot coolant return from the heater matrix in the boot cooled? If not, I’m thinking to cut both pipes at the sill and attach a loop of 16mm coolant hose to bypass the entire rear system system.

Thanks
 
The coolant will have a lower temperature on the return, but you don't need to 'complete the circuit' - doing so may reduce the effectiveness of the front heater due to the flow being reduced, the rear heating will have a flow resistance due to the length of pipe run, if you bypass close to the engine bay, this resistance will be greatly reduced giving an easy path for the flow, rather than a higher resistance path through the front heat exchanger. In short, better to blank off (or use a restrictive loop) than simply link the flow & return in, or close to the engine bay.
 
Hello Graculus,

Thanks for the offer.

Eventually we fitted a hose clamp as you described. I now have corroded ACE pipes, which apparently need replacing. Is this a difficult job? Could I at the same time replace the heater pipes whilst I am on.
 
Hi, i'm new here from the Netherlands and would like you help you all with a cheap simple solution for my 2017 L405 SDV8 4.4. Autobiography with 105k miles:

I made a bypass solution in a very simple way. A piece of EPDM hose 15/25 (15mm inner/25mm outside) thick and 1 meter long. Hose can go up to 120 degrees. I also had a coolant leak above the rear subframe so a very difficult spot. Thought of several possibilities but this is the simplest solution and costs 2 hours and 10 euros for the hose (1 meter). The aluminum pipes are loose about 1 liter of coolant when cutting the pipes. Be careful because at the first cut the coolant squirted out. So put on safety glasses and old clothes. I secured the rubber hose to the diesel tank mounts with tie raps so it's rock solid. The epdm rubber hose is pretty stiff so I had to heat it with a heatgun. With water pump pliers and some pulling and pushing I managed to pull this hose 4 cm over the aluminum pipe. Used 4 stainless steel clamps for 2 euro. The gray electricity box is only needed to make the workspace a little bigger. I used a multi tool to cut the aloy pipes. Watch out for the red flat cable and black thin plastic tube. Because otherwise you got a much bigger problem.

What the consequences are for the operation of the 4 zone air conditioning in the rear, I was just curious about that. I can tell you now: the hot air just works in the back, also separately so you can still control left and right separately. Left 22 degrees and right 30 degrees just works. This hot air comes from the front and runs under the center console to the back with a black flat plastic tube. Air conditioning I didn't do anything to it so just works. So what is not working now that the bypass is made? Only difference is that the there is NO warm air coming from above. So the rear fan in the ceiling next to the interior light by your head is not giving out warm air. That's all but for me no issue.

Summarized: 2 hours and 12 euros (or like £ 10 pounds). Filling up extra coolant was needed due to the loss of1 liter. Only 0,5 liter was enough because the rear coolant circuit is much shorter now (i think 2 meters each pipe so 4 meters in total). And special thanks to my dad, he supported me.
Thumbs Up


Update 2 days later after the repair: coolant leak!
Big Cry
Oh no... not again... I looked under the car. I forgot to put an end cap on the cutted pipe to block the coolant circuit to the rear unit. Only a bypass is not enough so close the aluminium pipes (between the rubber hose on photo 2, on photo 2 these are open). 5 minutes work. There is apparently still plenty of coolant in the cutted pipe so that was the reason of the drops of coolant on the driveway. Now its closed and fixed
Very Happy
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IMG_3216.jpg


IMG_3223 pipes.jpg


rear hvac coolant leakage l405.jpg


This is the rear hvac heater control unit that needs coolant to heat (no. 5 in the drawin above). Part no. HY3218D283AA. This part is located in the trunk. It has 2x air conditioning connections (inlet and outlet) and 2x heater coolant connections (inlet and outlet). So in my case, this part is no longer getting coolant.

This part is located in the trunk on the left side, behind the grille (intake). Needs quite a bit of work to access this. Interior lining has to come off for a large part in the trunk. In many cases this is not necessary. The hoses are in the rear left fender. For this you have to remove the interior fender trim

HY3218D283AA rear hvac 4 zone heater airconditioning coolant leakage l405 range rover.jpg
 

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