Technical JTD making a noise after turning off

[TangerineTractor]

My JTD makes a sort of whining noise about 5 seconds after the engine has stopped, sounds like something spinning down or closing. Only does it if the engine is warm. Garage said something along the lines of many modern cards shut down electrical stuff and its nothing to worry about... Any thoughts?

 

[Ffoxy]

Cooling fan running or turbo spinning down?

 

[TangerineTractor]

Sounds like something spinning down.. hadn't thought of the cooling fan, but could give it a spray of WD40 I suppose... anything I could do to the turbo if it's that?

 

[Ffoxy]

With any turbo equipped car it is good practice to drive the last mile or two "off boost" so the turbo can spin down with the oil pump still pumping oil.

If you just drive hard, park up & switch off you could be promoting early turbo failure.

If the cooling fan is running at switch off thats normal... when the temperature needs reducing in the radiator core / engine. I dont think WD40 will do anything (its a releasing oil rather than a lubricant) as long as the cooling fan isnt squeeking.

 

[TangerineTractor]

Listening again, it's more like a creaky door closing than something spinning down.

 

[torchzack]

I get the same sort of noise, sounds like a draft coming through somewhere, then 'clinks' and turns off, always just assumed it was the cooling fan. As far as i remember turning on the engine for 5 seconds and turning it off will produce the noise and so i guess it wouldnt be the turbo

Zack

 

[vladof]

It's the cooling fan followed by the relay turning it off. It's designed to work 5 seconds after power off as far as I know.

I hear it too and mine is a petrol so I can't be the turbo.

 

[TangerineTractor]

An update. May be a coincidence, but it doesn't do it every time, and it's not related to engine temperature. However, it hasn't done it when the AirCon is set to AUTO, ie the compressor is running. So is there some sort of sir intake flap or something that is closing when the ignition is turned off?

 

[vladof]

The AC would just be louder than the sound you were hearing.

Only 2 things can make a noise after ignition off:

1. engine fan, which still blows air in a little while after power off
2. air intake control valve servos, which power themselves off 4-5 seconds after engine switch off. Anyone who cleaned the valve noticed the noise.

Anyway, it's nothing to worry about.

 

[sussexa]

could it be your anti shudder valve on the inlet manifold could be a bit sticky?mine is free enough to open and shut by hand against the actuator.

 

[TangerineTractor]

could it be your anti shudder valve on the inlet manifold could be a bit sticky?mine is free enough to open and shut by hand against the actuator.

No, the engine is definitely off and it's a sound o something spinning down or closing.

 

[TangerineTractor]

air intake control valve servos, which power themselves off 4-5 seconds after engine switch off. Anyone who cleaned the valve noticed the noise.

That sounds plausible. As I said, it sometimes doesn't happen, depending on the AirCon settings.
Any chance of a description of how to find the relevant parts, and what could be done to quieten them? I'm fine on electrics and fittings, but not really any good navigating my way around the engine bay!

 

[vladof]

There's no actual way to quiet them, as they do this noise from being brand new, so you can't really lubricate anything. You just have to live with it.

May I ask why is it bothering you so much?

 

[TangerineTractor]

There's no actual way to quiet them, as they do this noise from being brand new, so you can't really lubricate anything. You just have to live with it.

May I ask why is it bothering you so much?

Because I've just bought the car, it's quite a loud noise, and I wanted to know what it was and if it was resolvable.

 

[Shadeyman]

The servo's in the head lights make quite a bit of noise when they are faulty, could it be the headlight servo's your hearing?

 

[TangerineTractor]

The servo's in the head lights make quite a bit of noise when they are faulty, could it be the headlight servo's your hearing?

I thought maybe that, but when do they actually operate? The adjusters work fine with no noise.

 

[vladof]

They only operate when adjusting them but if they're broken they buzz until you shut down the engine.

Water pump, air admission valve or fan. Either of which you cannot do anything about to make them quieter. I hear them all the time, don't really care, actually think they're cool sounding like a jet plane powering down thing thingie.

 

[TangerineTractor]

Just wanted to resurrect this thread...

The car is still making this noise, not every time I turn off the engine, but often enough to notice. I thought it had stopped, but it's been doing it the last few days, and it's actually changed a bit - I get the original loud creaking noise, but it seems to take longer and now fades out, sound a bit like a motorbike disappearing into the distance. I guess maybe the cold weather is making whatever it is take longer to close? But I'm concerned that whatever it is sounds like its struggling now, and may posisble one day stick on trying to close, and flatten the battery? Sounds like its coming from right at the front of the engine bay,drivers side. Could it be anything to do with the headlights? If it's the adjustermotor, can it be disconnected or a fuse removed?

 

[TangerineTractor]

Bumping this. Anyone help?

 

[cledan]

The headlight adjusters may be possible, do you ever adjust them via the load compensators? set that to zero to see if that makes a difference?

On my Alfa if I gave it a bit of stick with the A/C on the fan often carried on for a few seconds, sounding like a jet landing, bit of a whoosh, the condition of your fan motor may affect the sound though, and I think you can disconnect the fuse for this so you can work in that area safely?? These are only guesses mind