mex221

hi
putting xe in next week into my mk2 mex
was told i need an expansion tank for the radiator
i am running on the standard injection system and using the mk2 mexico radiator
does anyone know if i need one
thanks

as355f1

yes, and a different radiator

tabetha

NO, on the older radiator systems that were filled by the radiator they were only filled just above the top edge so there was a big space above the water level, this is your expansion tank, hence why they also had a tube leading from the rad cap in case they expanded too much due to being overfilled.
So plumbed correctly there is no reason you can't do without one, as the rad has one, may have to bleed the system though by disconnecting from the highest pipe/point till air free water comes out, expansion tanks took care of the de-gassing owing to the position of them being the highest point, or at least their bleed hose.
tabetha

as355f1

Sorry tabetha i totally disagree, i guarantee if you use the standard mk2 rad it will have overheating problems, i would use a corsa diesel radiator as there a thicker core and make a mounting bracket for it, then fit your header tank on the bulkhead, then you can also fit the telltale pipe.
I agree it could be done but there is a high risk of getting an air block and overheating.

mex221

thanks for replies
has anyone actually done this conversion and what rad or expansion did you use
thanks

as355f1

done the conversion on other cars but not a mk 2, i use any vauxhall expansion tank, corsa ones are quite small and do the job fine.

tabetha

I had a 2.1 pinto running around 180 through the std 1600 mk2 rad, was a new rad, but as far as I can remember std, I was more meaning the principle, it can be done without a expansion tank rather than be safe with a std 1600 rad, the mk2 has a massive frontal area for cooling compared with most modern/ish cars so that helps, could just get a thicker core one made ?
tabetha