Normal
I'd suspect the cap, too. Also, make sure the rubber hose/tube that goes down into the coolant tank hasn't fallen off. If it has, that would let coolant flow into the tank when hot, but not go back into the rad when it cools back down...it would be sucking air, which could cause the boiling sound when hot. Just a thought....and....mine has run hotter this summer than it ever has before...well over 1/2 gauge, and the fan runs quite a while once I get home...but I never heard it boiling in the overflow tank. I could look at the tank, and SEE the coolant moving, but I never actually heard it...
I'd suspect the cap, too. Also, make sure the rubber hose/tube that goes down into the coolant tank hasn't fallen off. If it has, that would let coolant flow into the tank when hot, but not go back into the rad when it cools back down...it would be sucking air, which could cause the boiling sound when hot. Just a thought....
and....mine has run hotter this summer than it ever has before...well over 1/2 gauge, and the fan runs quite a while once I get home...but I never heard it boiling in the overflow tank. I could look at the tank, and SEE the coolant moving, but I never actually heard it...
