OVERHEATING

one last thing one of the radiator pipes is under pressure and one can be under vacuum
the one that is under occasional vacuum usually has a spring in it to keep it in shape and stop it collapsing... i can never remember which one

aftermarket pipes sometime do not come with the spring.....

you should be able to feel it if you give them a squeeze.... they would not have wasted the time cost and effort to put them in if they didn't think necessary. does your pipe have one

Dave