Cadillac Repair: Coolant temperature and pressure problems, cadillac seville, coolant temperature

Question
1994 Cadillac Seville STS 4.6L
When flushing the coolant and adding mixture, after getting air out. The car seems to be running real high at 112 celcius and rising but when pressing the gas temperature drops. Even when doing a pressure test it doesn't hold it's pressure at all. What can I do and how do I go about it? Thank you Derek

Answer
You did add the supplemental sealant tablets to the cooling system as required by the manufacturer, YES ?. If NOT, Go to any auto parts store and ask for them.

The engine normally runs at approx 112 celcius and the cooling fans should turn on shortly.

As to the pressure testing, Do you have any external leaks ?. These engines are well known for leaking head gaskets.