hi guys - 5.0 supercharged new to me and I’m getting no heat in the cabin… any common faults? I have read the fbh diverted valve can get stuck? Current stable:
2015 5.0 V8 S/C AB
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

not sure whether a 5.0 petrol has a fuel burning heater ( and thus no diverter valve ? )

if you turn off the AC, do you get any heat at all, and what is the engine temp guage showing ? V8 or else ...

It defo has one as i have the remote for it and can see the gear under the bonnet Current stable:
2015 5.0 V8 S/C AB
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Ok - so, does the engine get up to full temp ? V8 or else ...

It does indeed Current stable:
2015 5.0 V8 S/C AB
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

This sounds like a blend motor/flap getting lazy.
If you've got access to a GAP tool or similar, look at live values for the heater flap positions. L405 2014 SDV8 4.4 Autobiography
Corris Grey
Previously 2011 D4 SDV6 HSE Santorini

Jack - 2014 L405 Range Rover SC V6 Luxor metallic

I have experienced problems in the past with my range rovers heater. Particularly when I turn on sync for the front driver and passenger climate control. The driver side will stay cold and the passenger side will blow hot. Sometimes it happens, sometimes it doesn't. Just hoping it will work correctly when the weather cools down.

If you are getting *no* heat, it's most likely the FBH diverter valve or electric water pump.

I just had exactly the same issue - air con working perfectly, but no heating. The diverter valve isn't monitored, so doesn't show any codes. I believe the part from factory was made by Bosch anyway, so order a Bosch one and save yourself £100.

Lift the car and remove the front driver wheel, put on an axle stand
Remove the rear wheel arch section
Undo the clamp bolt and loosen the fixing bolt for the FBH exhaust
Remove front driver plastic panel in the engine bay and you'll see the FBH slotted down the side of some plastic trim by the brake servo
Remove the bleed hose and coolant hose into the top of the FBH
Undo the multiplugs
Undo the 2 M10 bolts securing the FBH
Undo the 2 bolts on the strut brace and lift it slightly
Pull the FBH out, rotating as you do
You'll see the water pump on the side, the diverter valve is underneath (i tested the water pump with a multi meter and it was all good)
Heat and remove the 3 hoses on the diverter valve
Undo the 2 screws and remove
Reverse process to fit a new one. Get the lube out and smear some the hose barbs and outer edges of the hoses to aid refitting and getting the hose clamps back in place

I lost about 1L of coolant in the process, but once all back together, it's good practice to bleed it all back through anyway with the heater set to max and engine running, then rev to 2,500 rpm for 30s a few times

The job took about 2 hours. Aside from the jack, all you need tools wise is a small socket set and some hose pliers.


Hurrah, it was lovely to have heating back! 2015 Range Rover Autobiography 4.4 SDV8

Last edited by garyRR on 10th Oct 2025 1:23am. Edited 2 times in total

.. 2015 Range Rover Autobiography 4.4 SDV8

Thanks gary - I’ve got another diverter although unbranded i think i will just swap the solenoids provided they fit.
When you say heat the hoses is that needed? What with as guessing not an open flame?

Also, the pump - im guessing this would only cause a problem if the fbh wasn’t giving hear as the main system will be using the water pump to get the water round?

How do you test that? Continuity?

Thanks Current stable:
2015 5.0 V8 S/C AB
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

If you read the forum, people warn against the cheap diverter valves - people have had issues with them failing. The Bosch one is around £100, genuine £200.

I found the hoses needed heating with a heat gun (hairdryer works), because after 10 years, they were pretty well stuck on to the outlets of the valve.

Water pump i just tested the resistance with a multimeter.

Last edited by garyRR on 17th Oct 2025 10:34am. Edited 1 time in total

Tbh I did read them and some of the newer comments say you can free the old solenoid off as it’s full of crap. That is the plan a - the plan b is to put the solenoid from the cheap one in it with some rtv as the negativity i’ve seen towards the cheap ones stems from a weep coolant unless youve seen anything else?

Cheers Current stable:
2015 5.0 V8 S/C AB
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

So on my fbh woes… the fbh has been on for 5 mins and in the canine it’s blowing from the windscreen vents luke warm at best… could it still be a diverter issue? As said engine gets to temperature fine. Pr could it be the elctric pump and diverter? Current stable:
2015 5.0 V8 S/C AB
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

So today I⁩ let fbh run for 25 mins still luke warm, interestingly when I started the car it was stone cold on the gauge - took 5 mins to warm as if the fbh hadn’t been on - but it had been as I could smell it and hear it and the orange light was flashing on climate panel… why are the odds of the electric pump and diverter failing would this cause my issues?

I’m wondering if the po never used the fbh so wouldn’t have noticed the pump had failed for a while and then the diverter after … thoughts? Current stable:
2015 5.0 V8 S/C AB
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF