my advice, buy new.
I replaced the one on my van as it was wrecked, held water but looked awfull and wouldnt have lasted much longer. bought a second hand one, it leaked, bought a recored one, it leaked, tried another recore and its been ok so far.
then the cossie rad blew the bottom row out, bought second hand, it leaked, got pissed off and bought a cheap ebay ally rad, spot on.
i weighed in 6 knackered radiators the other week