Engine cooling question

[IceFire]

Alright... so for some time now I've known to basically never operate the radiator controls for any plane equipped with a R-2800 engine (Corsair, Hellcat and Thunderbolt). The word a few patches back was that the radiator cooling system was buggered up and it caused a lot of drag and didn't prevent overheating. I've tested a tiny bit but I was never able to be really conclusive about it.

Does anyone know if that problem was ever resolved and I'm just relying on old information?