Upon hard acceleration, the temperature rises quickly, crosses the halfway mark and then goes back down and stabilizes?

Hi,

I don't feel the radiator would cause this to happen. When you replaced the thermostat, did you replace the entire thermostat housing? If so, my next question would be if all of the air was bled from the system.

The manufacturer recommends vacuuming air from the system and then filling it by allowing the vacuum to draw the coolant into the system. I attached the directions below.

Let me know how far past the center it goes and has it ever overheated since the work was done. One other question, and don't laugh, does the heater work?

Let me know.

Take care,

joe

See pics below.