Strange hum on CDT

[Dawn]

Okay, so yesterday I was polishing the car and I could have sworn I heard a really, really faint humming noise. No keys in the car, hadn't been moved in a while. After a bit I convinced myself the noise was actually outside and ignored it.

Today, I went out to roll under and try and see if it had the spring protectors on, and I heard the noise again. The car hasn't moved since yesterday afternoon and was locked.

Then when I started polishing under the bonnet just now I could still hear it - car still hasn't been running or anything but was unlocked this time.

Is this normal? If not, any ideas? I've never heard a car hum before, even this faintly! It kind of sounds a bit like the fan on a laptop.

[Avulon]

Probably require a little more info;


Is the car a 'highline' car with satnav etc?
How long between disturbing the car (opening a door/boot/bonnet) and hearing the noise?

Any disturbance especially to a highline fitted car wakes the satnav and video module and the fan on the video module is often audible. On a non-highline car I don't know of anything that should create a noise in this way without the ign being being switched.


P.S : just thought better ask ; manual or Auto?

[T-Cut]

I used to have a Rover 420GSI that did something similar. Like a faint trumpet type sound lasting several seconds. Never did fathom the cause, but I reckoned it was pressure relieving, something, somewhere.

TC

[Dawn]

Hi

Its just the basic original cassette payer, radio and changer unit in the glove box. The car is automatic. You don't need to disturb it at all the very faint hum is constant. I have no idea if it does it when running as its such a faint noise it wouldn't be audible over the engine.

[Davy]

if you car has a fuel burning heater it could be a problem with it .My car was doing something similar and after i disconnected the fbh it has now stopped but i have not yet investigated further.the fbh is located in front of the Battery box and is rectangular with water hoses attached. https://www.youtube.com/watch?v=mqKy04HwdWw

Davy

[Dawn]

Hi Davy, the sound on the video is very similiar but louder. My car does have a box there, but it has two hoses to it if I recall. It's pouring down right now, but as soon as it stops I'm off out to put my ear to it! If it is that, how do I disconnect it until it can be investigated please?

[FrenchMike]

if you car has a fuel burning heater it could be a problem with it .My car was doing something similar and after i disconnected the fbh it has now stopped but i have not yet investigated further.the fbh is located in front of the Battery box and is rectangular with water hoses attached. https://www.youtube.com/watch?v=mqKy04HwdWw

Davy

Hi Davy,if you want to have a running FBH ,i can help :}

Mike

[johnnyb44]

if you car has a fuel burning heater it could be a problem with it .My car was doing something similar and after i disconnected the fbh it has now stopped but i have not yet investigated further.the fbh is located in front of the Battery box and is rectangular with water hoses attached. https://www.youtube.com/watch?v=mqKy04HwdWw

Davy

Hi. Mine did this to..The fan on the FBH would hum merrily away if I locked or unlocked the doors or opened the boot for a few minutes. I disconnected the power supply to heater to silence it until I got a reconditioned PCB board. French Mike is the resident guru on these things if you need to know more. If memory serves me right I cut the K bus wire to the FBH because it can cause it to randomly run the fan and from memory ( a bait a little vague ) is not needed for the fbh. Mine now works perfectly , even with the k bus wire chopped off. Before attempting any of this though please have a good search on the clubs posts about this and get some advice off people who really know what there talking about because the last thing I would want to see is that my advice is wrong.

[Avulon]

Hadn't thought to ask about an fbh. If it is this making the noise, then remove fuse 8 from the underbonnet fuse box to disable. Or just disable it and see if the noise goes away. If you do cut the k-bus wire then try not to cut it too close to the plug otherwise it'll be difficult to reconnect should you ever want to.

[Davy]

Hi Dawn there are two plugs on top of your fuel burner and i just unplugged them for the time being to stop it working or you can pull the fuse already mentioned above.

[Davy]

Hi Davy,if you want to have a running FBH ,i can help :}

Mike Hello mike i am going to get in touch with you when i get round to this job but a bit busy at the moment cheers

Davy

[FrenchMike]

Hello mike i am going to get in touch with you when i get round to this job but a bit busy at the moment cheers

Davy

OK,you have time till winter :}

[Dawn]

This is weird, there was a lot of road noise on our street this morning and I struggled to hear the noise, but it DID seem to come from the general vicinity of the battery/oil burning heater when I out my ear there. However, I took out the fuse, and it still made the noise. I unplugged the two plugs on the heater, and yep, it still made the noise. The car seems fine, so I guess all I can do is wait and see what happens...

[FrenchMike]

This is weird, there was a lot of road noise on our street this morning and I struggled to hear the noise, but it DID seem to come from the general vicinity of the battery/oil burning heater when I out my ear there. However, I took out the fuse, and it still made the noise. I unplugged the two plugs on the heater, and yep, it still made the noise. The car seems fine, so I guess all I can do is wait and see what happens...

Under Bonnet fuel pump ?

[Dawn]

How can I tell please?

[FrenchMike]

How can I tell please?

It's the aluminium vertical tube rear the battery.
turn the ignition on and you must hear a regular purring ...

[Dawn]

Hi

Typically I got outside and the heavens opened. What I have managed to gleen is this:

Putting my ear to the pump, the strange noise sounds no louder than it does putting my ear to the FBH. However, turning on the ignition, the pump definitely kicks in - the thing is, I wouldn't describe the sound as a purr, its more like a very loud motorbike!

I have heard this sound before when I kill the ignition, as it carries on for a few seconds before stopping.

Does this growl rather than a purr mean the pump is had it? Surely that wouldn't be the constant hum, though, if the pump only kicks in with power, because the hum is all the time?

If the noisy pump needs replacing, where is the best source? And is there a how to as it looks relatively simple, and I need to keep my costs down!

Thanks

Dawn

[FrenchMike]

Hi

Typically I got outside and the heavens opened. What I have managed to gleen is this:

Putting my ear to the pump, the strange noise sounds no louder than it does putting my ear to the FBH. However, turning on the ignition, the pump definitely kicks in - the thing is, I wouldn't describe the sound as a purr, its more like a very loud motorbike!

I have heard this sound before when I kill the ignition, as it carries on for a few seconds before stopping.

Does this growl rather than a purr mean the pump is had it? Surely that wouldn't be the constant hum, though, if the pump only kicks in with power, because the hum is all the time?

If the noisy pump needs replacing, where is the best source? And is there a how to as it looks relatively simple, and I need to keep my costs down!

Thanks

Dawn

You have to know there is another pump INSIDE the tank .
Generally (it was my case) a Noisy UBpump is the sign of a dead Intank pump.

Remove the filler cap ,turn the key on pos 2 and go listening (you have one minute or so).

Mike

[Dawn]

How loud is the whine from the in tank one? I've tried really hard, but there is so much traffic going up and down, and the front pump is making such a racket, I can't be sure. I *think* I can hear the back one whine, and I definitely can hear something gurgling back there in the tank.

I have nothing to go by on the front one, as to what it *should* sound like, though, and I have just discovered the little bolt the bracket is supposed to fit on has no nut, so the bracket isn't even on it, and the pump is simply vibrating on everything around it. And typically, its chucking it down again.

I will go and try and video it....

[Dawn]

Hi guys

I think I've cracked the pump noise! If you watch this, you'll see how noisy it was, but then I discovered that it wasn't held in place by anything and was (and still is because of the weather) vibrating on everything around it.

When I touch it in the video and stop it vibrating, it goes much, much quieter for a bit until it moves and vibrates again. Is that the correct *purr* that was talked about earlier?

If so, then I just have to figure out how to find the right size nut, and how the heck to get it on in that small space!

https://www.youtube.com/watch?v=qkSiO5-m65U&feature=youtu.be

[FrenchMike]

Hi guys

I think I've cracked the pump noise! If you watch this, you'll see how noisy it was, but then I discovered that it wasn't held in place by anything and was (and still is because of the weather) vibrating on everything around it.

When I touch it in the video and stop it vibrating, it goes much, much quieter for a bit until it moves and vibrates again. Is that the correct *purr* that was talked about earlier?

If so, then I just have to figure out how to find the right size nut, and how the heck to get it on in that small space!

https://www.youtube.com/watch?v=qkSiO5-m65U&feature=youtu.be


Dead bearing to me :shrug:

[Dawn]

It doesn't make the noise if I stop it vibrating on the battery tray thing though. Is that still too noisy?

[FrenchMike]

It doesn't make the noise if I stop it vibrating on the battery tray thing though. Is that still too noisy?

The bracket must be tight around the big rubber damper .check the screw
(8mm socket)
And you must remove the battery ...

[Dawn]

Okay, dumb question but where is the big rubber damper? I have a feeling I am bits missing. Currently, there is a small bolt poking from the battery housing, and its loose, nothing attached. The pump seems to be hanging from the pipes and connections alone, hence the movement and vibration. It has a bracket that goes around it, with a fixing plate with a hole in. I had assumed this simply attached to the loose bolt with a nut. Does anyone have a pic what it should look like and what I need?

Thank you for your patience with a newbie girl

Dawn

[FrenchMike]

Okay, dumb question but where is the big rubber damper? I have a feeling I am bits missing. Currently, there is a small bolt poking from the battery housing, and its loose, nothing attached. The pump seems to be hanging from the pipes and connections alone, hence the movement and vibration. It has a bracket that goes around it, with a fixing plate with a hole in. I had assumed this simply attached to the loose bolt with a nut. Does anyone have a pic what it should look like and what I need?

Thank you for your patience with a newbie girl

Dawn

Here it is:

http://rovermg1.free.fr/rovermg/thumbnails/nlcvgUsTjcI926N8sfSI.jpg (http://rovermg1.free.fr/rovermg/images/nlcvgUsTjcI926N8sfSI.jpg)

http://rovermg1.free.fr/rovermg/thumbnails/xBuIqAvGw93Gup77fs5U.jpg (http://rovermg1.free.fr/rovermg/images/xBuIqAvGw93Gup77fs5U.jpg)

Mike

[Dawn]

Ah, I see now. The bracket is a bit different on mine, but I think I can get it back on now. Thank you for all your assistance!