Processor Temp seems excessive at 78 C with LCS

I have a Powermac G5 dual 2.5 GHz (June 2004) with LCS (liquid cooling system) system that I would like to sell, and I noticed that the operating temps of the CPUs are in the range of 73 to 78 degrees C. I got this system with no power supply from craigslist. I was going to sell the CPUs + LCS assembly, but there were no buyers on ebay, not even any lowball offers. So I put the CPU back in the system, ran thermal calibration, and used another power supply from a different system. So far there are no leaks, but it just seems unreasonably hot. My Powerbook G4 gets up to 62 C when the battery is charging, but 78 seems excessive. It doesn't matter whether the CPUs are idle or under load -- the cooling system kicks in and keeps the temps pretty stable, and the CPU1 and CPU2 temps are within 3 C of each other. I did quite a bit of video transcoding on it in the last few weeks and it's perfectly stable. So that's the situation.

My question is, is this a problem, and what can I do about it? I've thought about tearing it down and flushing the cooling system, but I don't know how to do that properly and it seems like it would take waaay too much time. Is it worth it, or is it fine the way it is? Should I wait until the next owner complains there is a leak or thermal shutdown starts happening? The only easy thing I can think of is that the ambient temperature was a little too high while running thermal calibration. Thoughts?