Hi,

This may seem to be a repeat of a lot of other posts but everything I can find on this weird fan noise is related to BMW era L322s and not the Ford era TDV8s.

Anyway, started getting this really annoying noisy fan noise from behind the passengers airbag, but it's not the ECU pack as it doesn't have one, nor is there an ECU fan on these, there's no fuse box fan that I can find. Not a whisltling or bearing type noise, more of a heavy buzzing.

Although one is strangely mentioned in the RR wiring diagram. Next step was the old fusebox cooling fan, but that doesn't exist in these either.

I've had the battery, ecu, all the trays & trims out in the engine bay, glovebox out, CD autochanger, pretty much as far as I can go without ripping out the fuse box itself.

I can't find anything in theat area that would make any kind of noise at all, I'm stumped and there is no schematic in the RR workshop books showing anything or any mention of a fan existing that's relevant to the late model cars.

It's intermittent, completely independent of anything I try in the cabin, not engiine speed, road speed related, doesn't appear to be linked to the main blowers or environmental controls, changes pitch occasionally but doen't appear to be in tune to anything else running in the car, runs for 2 to 10 mins at various speeds and then shuts off never to appear again till restart. Doesn't matter if the car is cold, warm or hot. On a short run, turn off the engine it'll continue for a minute or so then wind down to nothing.

There is mention of a cooling fan for the electronic instrument pack but that's on the drivers side.

Anybody come across this before ? Any ideas ?

Andy

I’d guess it’s the fuel burning heater operating, it’s located behind the wing / under the battery.

It is a bit of a disconcerting noise but completely normal when the temp. gets low enough for it to fire up automatically when starting the engine  Jonathan

2007 Defender 90 XS Hardtop

One possibility is that the noise could be coming from the climate control panel, not sure about your year car, but some control panels have a small fan built into the panel, maybe a possibility ?

Hi,

Many thanks for those tips guys, I've set the timed climate for breakfast so I'll check that in the morning and let you know.

I'll also pop the centre console panels, see if anything in there, noise has a habit of travelling so it's a bit hit and miss to trace the real source.

Cheers, Andy

If it's narrowed down to the climate control panel, removal of the panels is easy, but do it gently as there is an ECU built into the panel that controls all climate functions.
For removing the panels and stripping down the panel to get to the fan, there are some helpful videos on you tube.

Using a car stethoscope may help locating where the noise comes from.

OK, thanks, I'll see if I can narrow it down further.

Andy.

There's also a fan in the audio head unit.

But also to point out that the cabin blower can be found in the far corner of each footwell above the transmission tunnel. The bearings are known to wear and make squeaky noises.

There's no other fans in or behind the glove box.

The only other thing I could think of is that the cheap foam which joins the ducting to the outer air vent has been damaged and could be causing a whistling sound. 2015 Range Rover Autobiography 4.4 SDV8

I might know what you´re after, although have no answer, unfortunately.

Is the sound like a fan going on for a little while and then back off? Like you would be increasing the fan speed yet at the same time the interior fan can be low, high and even off, doesn´t matter? Sometimes it sounds almost like a gentle pressure relieve valve, small hizz but more towards fan sound still.

And it comes and goes during the whole trip you´re driving.

Definetly not a fuel burner, as you can´t actually hear it when the car is running, just the ticking of it´s fuel pump is audible. And even when the car isn´t running and the FBH is on, the sound you hear comes from the interior fan. Besides the FBH doesn´t change it´s combustion chamber fan speed much when on heating cycle, just the amount of fuel been used by the interval of fuel pump ticks.

And to give some leverage to a strong opinion not being the FBH, mine was broken for a while, I mean really broken, completely dead and was replaced with a new unit, and the sound was still present when driving.

At first I thought that it would come from the recirculation, as the sound of airflow usually ( in many other cars ) changes quite drastically when recirculation is active. But it´s not that either, as I have the function disabled now.

So if you come up with something, I´m all ears and eyes! -07 Stornoway Gray TDV8

Hi,

Many thanks KF. It's not the FBH as I sat in the car yesterday when it kicked in and that fan is a distant hum, but thanks for confirming with your experience.

I sat there for must have been 10 mins just flicking everything on and off, different road and engine speeds etc.

Then had a light bulb moment watching TV last night, it's not a fan it's a pump, the noise playing over in my mind so I just checked this morning, it's definately some sort of pump, perhaps resonating or the mountings loose and drumming.

By the way it's acting, I'd say it's charging some sort of accumulator, i.e. it's running to a point then tailing off. Now back to the books so see what pumps we have.

Many Thanks, Andy

Hi,

After searching round with the stethescope it's definately the FDR fan, if you follow the noise back from the battery bay it's loudest touching the bottom battery tray. Also there's a wee gap in the OS arch liner I managed to poke the probe into to fish around to the FBH body.

I though it might be the auxiliary water pump but that's purring nicely.

Confirmed it by pulling engine bay F13, noise gone, put back in noise is back.

As the FBH is still working fine I've plenty of time to hunt around for a replacement, not cheap though I'm sure.

Many thanks to all for your help, cheers, Andy

Good to hear you’ve located the source of the hum although just to confirm it was the FBH fan after all, as not familiar with an FDR fan? Jonathan

2007 Defender 90 XS Hardtop

Yes sorry, to clarify its the FBH water circulation pump on the FBH itself.

New one is about £170, but can get good used for £60. Pt No: 7.02073.20 seems some BMW & Ford models i. e E53 use the same.

I might just strip it for the experience, it could be serviceable but I doubt it.

Andy