Could be. But, as soon as I would drill a tiny hole, just to release the pressure, the temps would go back to nice and cool, even though the top gasket/lid/cabl

Could be. But, as soon as I would drill a tiny hole, just to release the pressure, the temps would go back to nice and cool, even though the top gasket/lid/cables is still in place. So my bet stays with pressure build-up. It's not that I tried the whole thing once. I had several prototypes and spent at least two years trying various things before I finally gave up and switched to passive air cooling exclusively.