Morning, freezing here today at -4 and no warmer in the car (except for the steering wheel)

Within a few minutes of starting the car i get warm air coming out of the vents but after 10 minutes it blows cold. Adjusting the temperature, fan speed and turning on all vents doesn’t make a difference. The only difference is that the drivers side (right) is slightly less cold than the left side.

I’ve seen a few posts but nothing quite matching my symptoms. Anything obvious worth checking to narrow down the issue? 1995 4.6 v8, green/tan (long gone)
2005 4.8iS X5, blue/black
2011 4.4 tdv8, black/black (gone)
2003 3.0d X5, Oxford green/black/manual
2021 p575 SVR, BR green/vintage tan

Right looks like this a mixture of both valve units not working:

FBH coolant valve: There is some warmth in the cabin while the car is warming up but once the car is warm the heating goes cold. Took off the front left arch liner, looks like a mission to fix

Heater control valve: left side is warm (in the above scenario). Right side cooler. On the 4.4tdv8 this is bolted to the inner wing under the fuel filter. How on gods earth is it possible to change this without stripping loads of stuff out? Couldn’t get to 2/3 pipes

Anyone done either of these and have some tips? 1995 4.6 v8, green/tan (long gone)
2005 4.8iS X5, blue/black
2011 4.4 tdv8, black/black (gone)
2003 3.0d X5, Oxford green/black/manual
2021 p575 SVR, BR green/vintage tan

Could just be the fbh changeover valve is stuck, when the fbh is running it circulates through the fbh and heater matrix in the cabin, once the engine is started the valve should switch so the fbh warms the engine too, once up to temp the valve shuts off the fbh side of the circuit and it all switches back to just circulating through the engine to provide the warmth.

If the FBH valve is stuck, it will circulate warmth to the heater matrix, but once the engine has warmed up the Fbh will shut down yet the coolant to matrix will still be circulating just in the FBH circuit, or not circulating at all as the Fbh pump will have cut out. At least you know the heater is functioning, so it should just be the valve.

So I would start with that valve first. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
Fiat 500x 1.4 multiair Lounge 2015
2010 LR D4 Commercial 2.7 TDV6

Thanks for that info, sounds like the cause to me.

Is this the one strapped to the FBH? 1995 4.6 v8, green/tan (long gone)
2005 4.8iS X5, blue/black
2011 4.4 tdv8, black/black (gone)
2003 3.0d X5, Oxford green/black/manual
2021 p575 SVR, BR green/vintage tan

Mine is in my son in law's garage right now with a similar plumbing problem.
In my case 2 of the 3 metal pipes attached to the inner wing started leaking like a sieve.

It is an absolute PITA to remove all the gubbins but not impossible, although you are reaching in from the top and trying to work down into the depths without either falling in to the engine or massacring the paintwork on the outer wing.

No point in trying to get through from wheel arch or from underneath "we tried"!!!

The valve block has some 'wonderfully' positioned pipe connectors that we will try to rotate into meaningful positions upon reassembly.

We are aiming to replacing the metal pipework with modern reinforced rubber hose as the original part number price would purchase a small boat to go fishing with! We will make connectors from the ends of the metal pipes if all goes to plan and join it all together as much as possible on the bench.

The problem is that we will only know it fully works once all refitted and the engine running.

My tip "if not leaking, wear a thick jumper and gloves";

Best of luck. L322 3.6 TDV8 Vogue. 07MY
ML 320 7 Seat full leather etc. (The Black Pearl)

That does not sound fun at all.

I think I’ll start with the FBH changeover valve to get the heat sorted then look at the valve block for the l/r split.

Anyone know where the FBH changeover valve is? Is it the one on the fbh itself (fbh is on the bulkhead behind the plastic wheel arch liner). I used Realoem for my BMWs but can’t find an alternative for Land Rover - is it the paid for topix? 1995 4.6 v8, green/tan (long gone)
2005 4.8iS X5, blue/black
2011 4.4 tdv8, black/black (gone)
2003 3.0d X5, Oxford green/black/manual
2021 p575 SVR, BR green/vintage tan

Do you have 4.4 tdv8?

It is probably the FBH changeover valve.
It is located on the offside suspension turret. Easier to remove than the dual unit on the passenger side.

Remove it and take the top off. See how much movement the plunger has.
You can drill out some of the material from the swollen oring to give it space to move again.

Thanks yep 4.4 tdv8. Very glad to hear it’s more accessible. Is it in the engine bay under the air filter/fuse box or behind the plastic arch liner? 1995 4.6 v8, green/tan (long gone)
2005 4.8iS X5, blue/black
2011 4.4 tdv8, black/black (gone)
2003 3.0d X5, Oxford green/black/manual
2021 p575 SVR, BR green/vintage tan

The changeover valve would be my first point to check.

The WM is in the wiki to download if you haven’t got it already. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
Fiat 500x 1.4 multiair Lounge 2015
2010 LR D4 Commercial 2.7 TDV6

Remove the engine cover and follow one of the heater hoses from engine. Will take you straight to the valve at the side in engine bay.

My symptoms were the passenger side was the only side to get slightly warm. Rear heater was cold and drivers side only very slightly warm.

Had a go at getting this off but all the pipe clamp points are facing down so can’t get them off. Took the solenoid cover off in situ but can’t get the plunger or plate off - feels like something is holding it in 1995 4.6 v8, green/tan (long gone)
2005 4.8iS X5, blue/black
2011 4.4 tdv8, black/black (gone)
2003 3.0d X5, Oxford green/black/manual
2021 p575 SVR, BR green/vintage tan

Can you move the plunger up and down? How much movement?

Get yourself one of these

https://www.ebay.co.uk/itm/282458226072

Really need to fully remove to test properly.

I undid the tubes and pipes towards the bulkhead to give more room.