Spill water, i/o board heating too much

So yesterday I spilled water on my MBA, it turned off instantly. I directly went to the Apple repair store near where I live to know what to do. (The problem is that I'm living in Argentina since june and don't plan to go back to europe in months/years)

I let the MBA all day long to let them "clean it".

So now my computer is turning on but is really really slow. They explained me that the i/o board when connected heat way too much (I saw it and it's true) and the ventilator/fan is going very fast directly.

He told me that if we let the i/o board it will heat too much inside and that's not good and when we try to use the computer without it it's to slow to even open Word.

He is going to clean it a second time to see if it can change something but I'm quite hopeless.

Do you guys think the i/o board can really be such a problem for the MBA ?

Thanks a lot for your help !