Whistling Gas Tank - Solved! (10 year mystery)

[TankII]

I have had a whistling gas tank when the car is shut off for at least 10 years. I had replaced the check-valve on the tank at least once, and finally gave up trying to figure it out.
Well, I was testing my cruise control unit (non-functional for three years), and realized it was rusted out. To prevent vacuum leaks that were the probable cause of my lousy throttle response 2K to 3.5K, as well as the odd braking boost pressure issues, I bypassed the unit. Next day I drove the car to and from work and realized after I shut if off, the car wasn't whistling!
I did get a replacement unit, and I'll have to see if it starts up again, but for now, I'm much happier!

TankII

 

[shobote]

I had that syndrome and fixed it a few weeks ago; the vac line connector down by the radiator with the reducer inside was clogged, the diameter is very small so using a safety pin, opened it up and now whistles since.

 

[TankII]

I'll look into that as well once I've got the new cruise unit installed. It never hurts to go over everything with a fine-tooth.... Safety pin!