ive already decided to flush my system out very well and fill with green, as well as drop to a 180* stat, my real question is my temp gauge will be extremely high at a certain time and im asking those with exp if a certain problem is causing this such as intake mani gaskets/ stuck thermo or what. ill drive with normal temp, idle at normal temp (able to walk away for a few and return with no issues), but when it gets to normal temp and i shut it off then come back to it after a few minutes and simply put the key in the on position the gauge will skyrocket to well above 220, and at one point pinged with CEL. id let it cool down then check later. after the engine is shut off could the coolant be stuck in the block somehow(stuck thermo?) thus heating it up giving high readings? for the last several months ive noticed slightly higher operating temps but nothing harmful, figured my system needed service and id get to it when i could, which is asap now, just figured id try to find the culprit. thanks in avdance for any info on this.