Thanks for the replies. One problem is it is difficult to get a grip on the cap due to big air intake tube resting against it. So a marine mechanic here at the camp used a large channel lock on it and did not budge. Not sure if we pushed down hard enough due to the air tube mentioned above. But, on my toad , a '12 grand Cherokee, the cap turns half way then you push down and turn the rest of the way.
looks like i need to remove the air tube (and buy my own large channel lock); other choice is just drive it down the mountain cause i don't
think i lost much coolant. Was pulling the 5000 lb jeep up highway
18 from Barstow to Big Bear ca. When it over heated i unhooked the jeep and drove the rest of the way without trouble. looked like about a pint of coolant on the ground.