That's CRAZY,Ulf! I Bought a new "old-style" radiator cap,and I HOPE that works. The
"New-style" is 4-P.S.I.,(on truck now),and the old-style is 7- P.S.I.. If that doesn't work,I'm going to check the water pump for blockage(s),and completely flush and drain the radiator/cooling system. Hope our problems are not serious. These trucks of ours are like kids... they always need something to behave the way they should. HaHa!! Good luck!!-Bill