I have seen top tanks like that before, but just assumed that it was from some morn like me putting his knees there while working on something toward the rear of the engine.
Hard to believe vacuum from a stuck cap would do that ...
Most likely due to vacuum sucking it down maybe when the eng.heats up & builds pressure it will reverse its self.On a side note what's that 71 a RR or GTX.
phill,not the big pressure spring you see.turn rad cap over from your last picture.take your finger nail and pull the silver disc "mopar hanging vent valve " down.it should NOT spring back up but hang free from rubber . get a real mopar rad cap so you don't ruin another 956 rad. bob s @ glenray rad.com will fix you up. ronnie
turn rad cap over from your last picture.take your finger nail and pull the silver disc "mopar hanging vent valve " down.it should NOT spring back up but hang free from rubber
well bummer I remember putting a new cap on it a few years ago cuz it always spit on the ground after shutdown. guess I will put the old one back on
If the old one let it puke then either the psi was sky high or the main thick spring in the cap was weak. I would instead get a new one & just confirm the thin metal disc at the bottom is loose/free (& since it is new/likely the disc is good there)