Not such a silly question...had me scratching my head when I first opened the body. I had to do exactly what someone above has suggested and followed all the pipes back...and discovered:
-main rad
-intercooler (cools the air after the turbo has compressed it, thus giving more power)
-oil rad (which has an annoying little leak on the bottom pipe

)
If your's has no air con these 3 are def the best bet, as suggested by other's above.