"whistling" VTEC Solenoid?

I have a 94 GSR and after driving for 30-45 minutes there is a light to medium high pitched hum coming from what seems to be my vtec solenoid? Is this normal or needing to be replaced? Or is there a fix for it that I can do on my own? What does it sound like to you?

Do you have an oil leak in that area? When the cam plug starts to leak I’ve seen some that make a whistling type noise from there.

I havent checked, but I will certainly do so here shortly. Last night a few guys had mentioned that solenoid and possibly my intake manifold. Just trying to pin point the problem. I’ll check - and thanks for the reply.