1998 V70 Problems

I have two problems with this vehicle:

- At around 70mph, during hot days, the car has a loud whistle,
constant pitch, it comes on and off when you go faster or slower. Tried
windows, A/C vents selection to no avail.

- Keep getting code P0455:
It refers to the evaporative system, gross leak. I have inspected all
hoses and gas tank cap; they seem to be ok. The only thing i noticed is
2 ports on the side of the air filter housing top. One of them, brass
fitting, has a hose that goes to the engine. The other port, plastic,
has nothing connected to it. Could this be the problem? Has anyone
experienced anything similar? The vacuum routing in the sticker under
the hood does not seem to clearly represent this vehicle.

Are these issues common to this vehicle.

Thanks for any and all help

 

I 'm sending you this link, try it, it's a very good place for info on
Volvo's.
http://www.volvospeed.com/maintence.htm
Hope it helps, it does to me.

 

Thanks for your reply and for sharing this link.

AS