I got a HKS R-type FMIC last year and on the way home the external air temps were ~28-30 dec C and my air con was cr@p where previously it was VERY cold
Well, most know my story now so, I have only had the car back a short while (couple of weeks) and I have a new FMIC, new Air con rad and new water rad ....all new rads at the front ....ANYWAY, it's all new and fully regassed and if the external temps go over ~25 dec C then, I have to leave the AC switched off as it's just hot air coming in
I had never read about this problem on here, SF or other boards but, this is a problem of blocking the AC rad with the FMIC so, if AC is a must for you then the FMIC is not for you.
I might remove the new AC rad and at least get a little more air to the water rad since, I won't be using AC anymore.
Oh, water temps are fine btw so, no problem their.
I hope this helps