coolant spray near flange -> coolant light -> drop in engine temp

[alimo20]

I have a leak from the coolant flange as my botch job for it's repair has not yet been remedied. I need to find a proper garage/time/place. anyone live in Philly with a garage i can use for cpl hrs tomorrow?

Anyway - per the title post, I am getting coolant spraying all from the back of the engine even into the fireproofing material. this occurs when I am driving (and I'm guessing as I don't have a camera in the engine bay, can only see after I park). After this (probably) occurs, I get a coolant warning light and then immediately the engine temp drops about a quarter. 30 seconds later engine temp recovers and coolant light goes off.

What is going on?

[diagnosticator]

Since you are loosing coolant, when the level drops enough, the coolant level sensor in the expansion tank senses the low coolant level. Then the temperature sensor goes dry. That is why the gauge needle drops due to the lack of coolant surrounding the temp sensor..As the coolant drops further, there is not enough coolant to flow to the radiator, so the engine over heats.

[alimo20]

but i wouldn't know of the over-heating aside from secondary side-effects like a head gasket failure or warping of the head etc right? if there is no coolant for the temp sensor to read, then any measurement of it is just air/steam or nothing so i can't really trust it's output to the cluster to be accurate.

wonder if i overheated the engine and didnt even know it.