I found this on a site describing Mocal oil coolers, I'm guessing Setrab would be similar. The same supplier (
Thinkauto) sells Setrab but doesn't provide the same info.
Pete
"Maximum working pressure on the standard range of coolers is 10 bar (150psi)although each cooler is tested to11.5 bar (170psi) this is adequate for all but the most arduous motoring applications, however some customers prefer a higher pressure rating, for instance where the pressure by pass valve does not provide enough protection as in high rpm in cold start up conditions or on dry sump installations.
We have introduced a heavy duty (HD), 12bar (180psi)working pressure, version of the cooler which is dimensionally similar but has aluminium castings between the plates, on the standard cooler this is the weakest point where they are unsupported by fins or tubulators, There is also thicker material in some areas. These coolers are about 18% heavier. Because of their construction they are easier to build in the bigger sizes hence a cheaper price."