My 2005 Impala (base 3.4) has a new engine and transmission. We recently noticed a very big coolant leak, and found the radiator was cracked.
We replaced the radiator, thermostat, and rad cap, and now having running hot/overheating issues. We have bled the air, but still no luck. The car can idle for a long time and will remain at the half-way point (which is still hotter than its normal operating temperature). As soon as we hit the road, it jumps up to 3/4 and stays there.
The heater blows hot air fine, and we are not noticing any other issues. The thermostat opens and none of the hoses are visually externally collapsing.
Where do we go from here?
Why do you think it is overheating? Is it based upo the dashboard gauge?
Did you install an OEM ACDelco unit, or an aftermarket (Chinese) one?