The heat riser was rusted in the closed or cold position on my 216. After a lot of rust dissolving product application, I finally have it where I can physically turn it from the closed to open position. However, it’s not even close to being free enough to be turned by the thermostatic spring. The actual valve in the manifold passage is very rusted to the shaft, so I’m not sure if it could be freed up enough to allow its removal without destroying it in the process. I’m thinking that I may install a new thermostatic spring for cosmetics, but just leave the riser stuck in the open position. I never noticed any difference in cold starts years ago on my Malibu when I installed headers and cherry bombs on my 327. Does anyone else have any experience with repairing the heat riser to working order?
