I have pushed those beyond their limits as to test them.
When the red light comes on, it stops hashing as to prevent damage or cause fires.
Recycle your coolant as you may have grown air pockets; those need purging out.
Even in automotive cooling systems, air pockets can lead to all types of headaches.
Leave your pump's top screw "not tight"...
IF you have a SysCooling, make sure that sucker even works.
All the best
