kranje, two potential causes come to mind for the elevated engine operating temperature: stuck thermostat and less-than-full cooling system. What brand and temperature thermostat did you install? Recommend a Wahler. As mentioned it's possible the cooling system is not completely full. I normally fill the engine block via the thermostat housing before installing the thermostat. Before installing the upper radiator hose I attach a short piece of clear hose (same size as radiator hose) to the upper radiator connection and use it as a funnel to fill the radiator with coolant mix ... leave the cap off the expansion tank while filling the radiator. Once the radiator is full install the upper radiator hose, reinstall the cap on the expansion tank and run the engine with the heater on until the engine reaches operating temperature. It may be necessary to add coolant to the expansion tank so it's at the proper level when the engine is cold.

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Fred Hoelzle