I've been doing research on radiators, & my 1st 'experiment' will be a conventionally configured radiator (downflow design) with inlet & pressure cap on top. In reading about issues with conventional radiators, a common complaint is pressure venting due to the water pump + system pressure exceeding the cap's rating. Crossflow types like the Sirocco are supposed to avoid this because the cap is at the mid-point in the flow through the rad, which drops some of the pressure seen by the cap.

Here's my question: Is there any reason a conventional rad can't be fed from the bottom, instead of the top? This would achieve similar effect as the crossflow cap location (all the way to the end of the flow path) & any air could be vented using the existing fittings. I'm also considering the removal of the spring loaded seal, & moving the pressure cap function to a separate swirl can. By doing this, the existing over-pressure port could function as the air removal port in the top tank of the radiator.


What am I missing?

Thanks,

Charlie