stuck radiator cap

[Nlbloch]

I have a thermostat-style radiator cap that became badly corroded. I have soaked it in CLR and most of the corrosion dissolved, but I still have some crust that just won't disappear.

Worse yet, the hinged top won't open -- I can only access the radiator by taking the entire cap off.

Any suggestions on how to remove the remaining crud, and how to separate the top/bottom parts of the cap?

 

[chap52]

I would try soaking it in Apple Cider Vinegar for a couple of days.

 

[JBill]

White vinegar.

 

[ryanheacox]

If you know anyone with an ultrasonic cleaner that would probably do the trick also