Many airplanes such as some Spits and 109s had duel radiators were if one radiator was hit, the pilot could shut off the valve and prevent his coolant from leaking all out, giving one time to get back to base.
Although it is unclear if all 109s and spits that were intended to have radiator shutoff valves had them, many did and in the case of the 109, even the manuals indicate that they did, even if they were to be installed after the initial plane was shipped. Also, at least one of the very few remaining 109s in existence today also it installed.
There is a whole thread around this for the 109.
http://bbs.hitechcreations.com/smf/index.php/topic,305654.0.htmlMy wish is to have this feature added to the 109s and spits(duel radiator) and any other plane which it applies too.
109s..
g2/g6/g15/k4
spits
Mk VIII, Mk IX, Mk XIV and Mk XVI