you need run the pump consistantly to make a noticable effect

I did this before on my mpv to keep ac cold when waiting kids 2hrs in parking, 1.5L bottle finish in i think 10mins.... barely noticable difference in my situation.

But if your situation is moving vehicle & heat build up in engine bay, exhausting the heat would be first step instead of trying to cool down the heat.

Also, depending on car make model, having proper ducting/panels to guide the air thru may help