no, not at all. The races are super short sprints (5 to max. 10 laps on a 800m track).
Quite a few front engined cars place the rad in the boot too, to protect it from damage (intentional contact is forbidden, but crashes happen non the less), and that reroute adds so much capacity that engine heat is normally the last thing to worry about. Our Polo leaked all the time, we added 1 to 2 liters after every race
Sometimes cars ended up engulfed in steam on track, limped/got towed back to paddock, and a few liters and meters of gaffa tape later they started in the next race
Quite a few front engined cars place the rad in the boot too, to protect it from damage (intentional contact is forbidden, but crashes happen non the less), and that reroute adds so much capacity that engine heat is normally the last thing to worry about. Our Polo leaked all the time, we added 1 to 2 liters after every race
Sometimes cars ended up engulfed in steam on track, limped/got towed back to paddock, and a few liters and meters of gaffa tape later they started in the next race