I own a 2000 Pontiac grand prix GT 3800 series II. I have had issues with it running hot in the 225-235 range. After replacing the water pump, thermostat, temperature sensor, and flushing and filling the sytem as well as pressure testing the radiator for leaks the engine still runs hot. I notice the high fan speed doesn't kick on until the car reaches about 235 and that is also when the radiator hoses seem to be filling with pressure. I have no idea if this is normal or not. It just doesn't seem right to me. The car always stays under 235 tho.. it gets to 235 and the high fan comes on and the hoses build pressure lowering the temp to about 210-220. then it slowly rises up and repeats the process. when driving at higher speeds the car seems to stay below 225. but at a stop light it will rise very soon. This seems odd to me because basically everything in the coolant system is new yet its still hot..? it is about 90 degrees out though so could this be normal or is there something else i can try? all i can think of is a bad gauge in the dash, or tuning the car so the fans come on sooner. I just dont know what else to try anymore though.car has 160,000 miles. any help is appreciated.
