Hello. I have a 2004 Transit, 2.0 turbo diesel panel van, 108k miles.
Last weekend I changed the glow plugs. To do this I had to remove the air resonator and disconnect the battery. Put it all back together and it started on the button. Job done.
Drove it yesterday and there is a bizzare sound coming from the air vent. There are four vents on the dash, two in the middle and one at each side. When it gets to about 2,300rpm there is a sound coming from the driver’s side air vent only, a sort of wind rushing type noise. This happens regardless of road speed or gear, will even do it when stationary.
Not sure if it’s connected to the glow plugs thing but I’ve never heard it before. The air filter lives on the driver’s side, right in front of the dash but all is fine there. I’ve checked the resonator again, all done up nice and tight. I’ve taken it up to 3,800rpm and it just keeps going, but as soon as I lift my foot off the throttle it stops. Can’t hear anything unusual from the outside, or not which I can hear over the engine at 2,500rpm anyway, can only hear it inside.
Any thoughts?
Thanks guys and girls.

Start with split in flexy pipes

Roger Whittaker trapped under the bonnet?

Hole in a boost hose or exhaust?

I’d go with split in turbo intercooler hose duct. I had similar in my focus and found pipe at rear of engine with large split in it. The engine also struggled to rev above 4000. £30 of ebay for new one and 20 minutes to replace.

Started with the obvious, but no sign of Mr Whittaker so followed the other advice and checked exhaust and flexi pipes, turned out to be both, sort of. The seal between the EGR valve and inlet manifold wasn’t on quite right, so something at the end of a flexi pipe in the exhaust system. I blame user error. Thanks all

It remembers the tune but has forgotten the words?