Whistling box after radiator cleaning
 

01 box, first time cleaned the radiator by removing the bumper. There was a caution stated on a thread that if the front trunk lid is not lower than the bumper, audible noise may develop.
Well my boxster starts whistling at about 79 MPH. When i took it up to 100 mph, it was LOUD!!!!
Tried reseating the bumper, but no success.
Any and all recommendation will be greatly appreciated
Thanks in advance

Typically the bumper/hood gap is cause of whistling in 9x6s (in 9x7s it's side mirrors). Quick test... put a piece of painters tape over gap from bumper to hood and re-test.

If no whistle sound then your issue is there. Proceed to remove tape and using the two upper most screws for bumper (under trim where hood latch is), adjust gap from bumper to hood. Visually you *think* it should be same as gap b/w hood & fenders but from factory it's actually about 50% larger than those on side. That said, you can also adjust hood's closing height too to ensure it's below the bumper. Pull back frunk carpet and adjust by loosening the two 10mm (IIRC?) nuts holding the latch receptacle a bit lower. Small increments here are all that is needed here and don't forget to also adjust the black rubber screw-in bumpers in corners of hood.

Good luck :)

Took your suggestion, pushed the bumper skin as much from the lip of the trunk. Went out for a drive and found whistling started at about 85 mph.
Lowered thr trunk by lowering the latch mechanism just a little. Adjusted the rubber spacer on each corner.
The best i can conclude, just a very light whistling. Noe.
Thanks much
Thanks