Board Thread:Questions and Answers/@comment-34561139-20190112235343/@comment-101679-20190608115358

I couldn't tell you that specifically because I haven't used IC2 pumps to cool engines, but I can tell you each BuildCraft pump can cool a maximum of one engine running on refined fuel. I tested it recently. I power my BC pumps with redstone engines, 2 per pump. (I might have tried 1 redstone engine per pump, but if I did, I guess it wasn't enough.)

I mention refined fuel specifically because I thik I remember reading combustion engines run cooler on other fuels. There's a table on their page.

(Note: MFE and MFSU aren't power supplies, they're just batteries.)