I have 95 Eldorado with 4.6 engine. I recently replaced a badwater pump, water pump belt and tensioner. I also checked thermostat and its gasket. The old water pump was dumping coolant out the weep hole due to gasket failure and worn pump. I also flushed the system. The system now has no leaks and coolant level stays stable. Although city operating temp is about 223-226, and if I idle for several minutes during city driving it gets to 230. On the highway it doesnt cool to less than 220, even with air on.I dont believe it is the thermostat, I know it is at least partially opening. I did the repairsthree days ago and have noticed the temp change for two days. Anybody have any ideas on what might be going on, before i drain system again and replace thermostat.

 

you seem very observant as to what it is doing.

tell us what the engine was doing BEFORE the pump replacement.
also, any overheating BEFORE te new pump?
what did you use to "flush"?

 

Before the new pump it was dumping coolant out of the weep hole of the water pump. It heated to about 248-250 and I immediately stopped were I was at and let cool down. Then I filled with water and limped home at about 235-245. It has never overheated prior to the water pump going bad. I flushed it with tap water just to make sure all the gasket material and sealant was out of the system.