How do you can loose a jammed radiator cap in a 1999 Pontiac Montana once you have turned it to the open position and you try to pull it unsuccessfully?

Answer 1

I had the same probleme. Finally I had to push down again and turn counterclockwise again and Bingo I got it out ! Answer 1 is correct, but did not explain that the cap was NOT "jammed." In the "old" days, radiator caps could be removed with a single twist to the "open" position you mention. However, the pressure of the coolent in the radiator, would often "blow" the cap out of your hand, and scald your hand, arm, and possibly your face and other parts of the body. This was NOT good !!! For SAFETY, radiator cap manufacturers designed a "DETENT" lock into caps which allow you to loosen the cap just far enough to allow the hot pressurized coolant to flow through the "overflow" tube to the coolant recovery tank. When you turn the cap to that detent position, it CANNOT blow off, nor can you remove it. By design, to "override" the safety detent lock, AFTER there has been time for the presure to neutralize, you must FIRMLY press the cap down, and THEN CONTINUE to turn the cap another 10 to 20 degrees of rotation, in order to clear the safety lock tabs, and THEN lift the cap off of the radiator filler neck. Hope this helps many. j3h.