I just installed oil cooler screens for my car today (my own design, bent metal mesh spray painted black and riveted to the inside of the rubber intake for the oil coolers), but while I had the nose off I took a look at the oil coolers. Does anyone know for certain what material the coolers are made of? They look like steel to me, which might explain why Mazda didn't bother putting a screen on them as the AC condenser is aluminum. If they are steel, are screens even necessary?

 

Aluminum.....the fins bend when they get hit with debris

 

Got a magnet?