Paul - Long ago, I did have many of the joints leaking. I changed all of the hose sections, replaced all clamps with good, sturdy stainless steel clamps, and tightened the "you know what" out of them upon installation. If you have old hoses, or original clamps, it is entirely possible for the leaking to occur at the joints. As for the pressure rating of the cap, unless the system is very hot, the pressure shouldn't build up to that level. I don't think that the proper cap is constantly relieving pressure during normal operation. Others may have an opinion on that. It certainly is better to have the correct cap, to avoid pressure-related damage to the system in the event of an over-heat. Toby Peterson VIN 2248 Winged1 --- In dmcnews@xxxx, "Paul Salsbury" <paul.salsbury@xxxx> wrote: > with this cap not releasing the pressure correctly in is forcing the coolant out through a rubber joining pipe.