High pitch whistle sound

[Naylz29]

Hello again everyone, I now own a Transit Mk6 2.4 duratorq 125 T350 chassis cab Motorhome. It has done just over 30000 miles and is a 2004 reg. over the weekend we went away for a 300 mile round trip, whilst driving I could here a high pitch constant whistle noise from the engine, performance seemed fine and the tone of this noise did not change when increasing speed or slowing down. When I parked up and opened the bonnet the noise does appear to be coming from the turbo side of the engine, it’s almost like the high pitch buzzer you get if you leave your lights on but I’m more convinced it’s some kind of air leak. If I turn the engine off it obviously stops, restart the engine and it reappears a few seconds after restarting, almost as though once pressure has built up sufficiently to make the noise. I am thinking a vacuum hose?? Are there any pointers as to where I should start looking, are there any common ones that go?? I am hoping it’s not the turbo bearing based on the grounds the sound doesn’t change if you rev the engine?? I realise I do have an intercooler too but that is lower down at the front and the sound doesn’t appear to be from there.

If anyone can offer any tips or pearles of wisdom they would be much appreciated. I am quite mechanically minded and can tackle most jobs myself, just don’t want to go replacing the turbo if it ain’t that.

Many thanks in advance

[metalworker0]

The usual place to look is the boost pipes ..look for leaks at the joints or cracks along them.

all the best.mark

[Naylz29]

IMG_1163.jpeg

Update; found the source of the noise. Turns out it is a failed vacuum purge valve/actuator, which I’m guessing has a diaphragm inside which has split causing the whistle noise. Can’t find this part anywhere, seems the ones listed for my transit mk6 2.4 duratorq don’t have the same bracket as mine, maybe an oddball as it’s a motorhome?. Anyway having googled it I am starting to think this allows vapour from the fuel tank to vent into the inlet manifold when engine off??? When I start the engine a vacuum sucks on the valve causing it to shut off the purge line?? ……..so maybe I could just disconnect it and plug the vacuum pipe end. Think it vents the fuel vapour into the engine to save dolphins or something?

[metalworker0]

think - not sure - this is the part number

4427199


found here

https://www.catcar.info/ford/?lang=en&l ... MzkyKzA%3D

i searched and only found it in foreign countries


all the best.mark

[Naylz29]

IMG_1172.jpeg

Don’t think that is it, thanks a lot for looking. The only one I have found that is anything like it is this, the bracket is clearly different but I think I can fabricate a plate to adapt it to fit. It is purely a vacuum operated actuator which opens or closes a vent once the engine is running and vacuum pump spinning. So going to try this as a temporary fix whilst I try and find an exact match. Thanks again

[knobby1]

IMG_1172.jpeg

Don’t think that is it, thanks a lot for looking. The only one I have found that is anything like it is this, the bracket is clearly different but I think I can fabricate a plate to adapt it to fit. It is purely a vacuum operated actuator which opens or closes a vent once the engine is running and vacuum pump spinning. So going to try this as a temporary fix whilst I try and find an exact match. Thanks again

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