Weird whistling sound, mostly at idle..

I've been using Yoda as the daily driver over these past couple of weeks, since the van is by far the best place to sit when I have a long way to drive. The bB corners on rails, but is as hard as a very hard thing on its firm dampers and even harder springs, the Pajero Mini is happiest at 40mph or when in low range and plodging in mud, so the Hiace gets the job more often than not, which is fine, but for this noise, which irritates massively as it's so much quieter than the Disco's 300 TDI engine in every other way.

I posted this at RR, Autoshite and Practically Classics too, but as yet, only one other forum member on these other regular haunts of mine has offered a suggestion and no, there is absolutely, definitely no leaking air between the intake behind the door and the associated pipework, all of which is present, correct and clean.

I'm hoping that someone on here might have heard a 3L doing this before now and may offer some wisdom.




Weirdly, although the engine is generally and unsurprisingly much less audible with the seat down and the lid on the battery tray (removed as I was going through the split charge relay and associated wiring at the time of recording), the sound when the engine is hidden away seems louder!
Baffled doesn't begin to cover it, I've been up close and personal with more distressed older vehicles since 1979 than I've had hot dinners and when I was still making my living at this stuff, I typically had far more complex machinery to cope with and had, right up 'til I posted this, never failed to identify the source of the problem. I once owned a VW LT, and even that hateful thing was rarely off the road for longer than a day, as witnessed by the gallons of gear oil that have run down the neck of my boiler suit over the years, 'nuff said!

Some muppet from the frozen North East wrote:

something about the air intake pipework not being the cause of this..

       
Sorted! Removal of the air intake grille, a wee splodge of bathroom sealant between the grille's seal and the surrounding bodywork, a few minutes to allow the sealant to set and I'm rewarded with silence . Well I say "silence", but this is of course a relative quantity and a Hiace, or indeed any vehicle which conceals a big old Diesel engine under its front seats, will never compete with a split new S-class Mercedes-Benz in the refinement stakes. But then I couldn't drive up the side of a muddy hill, sleep there in lovely warm conditions, cook and eat my rolls and fried egg, have a brew and then drive home, all in the supremely refined luxury car that I named above.

My conclusions?
1) I must never jump to conclusions.
2) A 27 year old van is better than a factory fresh German luxury car. And there begins another internet statistic that will, if left to grow and fed with plenty of manure, become a "fact" some day.

(Room full with monkeys & typewriters, complete works of Shakespeare, etc..)

Sounds like a good fix!
Beware leaving the front sunroof open for any length of time - the front rubber gets used to the angle and when you close it forms a slot whistle!
I added some foam around mine just under the front lip to stop it. I don't know why Toyota did the front one like that but it's very noisy - if you open it open then leave it open while you drive too!