Have you checked to be sure the fans are actually moving the air. IOW, could they be blocked by dust or "fuzz" [forgive the use of such technical language ] you don't readily see thus causing them to be inefficient coolers?

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~James Helbert~, Wytheville, VA
Providence Reformed Presbyterian Church, RPCUS
TheBibleAlone.com / The Edinburgh Inn
"Is this not a brand plucked from the fire?” - Zechariah 3:2