I drive a 63 reg Volvo FH.When I open either window I get a high pitched whistle.
Has anybody managed to track down where it comes from?
Is it not the wind that passes between the mirror arm and door frame.
I think its higher up on the cab.
Have you got spotlights mounted on a bar on top of the cab?
All ours do, and they all whistle.
Apparently it’s a well known problem when fitting light bars to the new shape Volvo.
No lights on top of the cab.
if the other post on Volvos is anything to go by its probably something getting ready to fall off
When our CFs came last year, most of them had an unbearable whistling noise when you were at motorway speed. It turned out that the windscreens hadn’t been sealed properly on them. Ryder just filled the gaps with silicone sealant. It cured the problem though.
Lol ,those swines at ryder stealing my glory 
It was a known issue that DAF released a bulletin about
the whistle only happens when I open either window.
Get some bells for it.
Love a truck with all the bells and whistles on it.
My old DAF had those stainless mirror guards on it. Used to whistle like kids with no dads. Was forever adjusting them.
DAVE Y:
the whistle only happens when I open either window.
The whistle is probably always there its just with the window closed you don’t hear it.
Does it make any difference if the window is part open or fully open. Does is make any difference if you have both windows open or the sunroof slightly open?
PaulNowak:
My old DAF had those stainless mirror guards on it. Used to whistle like kids with no dads. Was forever adjusting them.
mine had a lovely habit of folding the nearside mirror in at motorway speeds.the stainless guards deffo stopped the mirrors getting smashed as they were folded tight against the ■■■■■■■ cab …