Hey Scotty,
I have two 2008 Impala's, both with the 3.9 v6.
One was taken much better care since day one, the other I bought after it was abused for 12 years in a municipal fleet. While most of the issues have been corrected, I am chasing one outstanding problem. The 08 LTZ with 112000 miles runs hotter than the other 08 LT with 85000 miles. I have replaced the water-pump, the thermostat, and the coolant. I also replaced the radiator cooling fan with a cheap Chinese ultra-power replacement that I am not 100% sure is working correctly. The vehicle runs around 205F driving 50 mph. In stop and go traffic the car however between 225-229F. The temperature gauge is not indicating an overheat and the car has not actually overheated. It just runs hot in a range that I don't consider normal. The 08 on the other hand runs 195F at 50 mph, and 207F in traffic.
Two things I'm thinking -
Is the cooling fan activating on schedule? If you turn the A/C on the passenger side fan is not always on. It will turn on, but it is not always on. Do you have the triggers that activate both fans and their condition to do so?
Could the radiator not be working right? I don't believe there is a blockage in it, and I bled the coolant system when I changed fluids using AC Delco coolant. But could this radiator just not be dissipating heat like it is supposed to?
I ordered a new coolant cap, FWIW there is no indications that has been any leaks around the cap and there are no indications of coolant leaks in the system.
Thanks,
John
The problem was two broken wires in the car's harness, the electrical current was jumping from one wire to the other giving indications of electricity being supplied but the fan not working because it was not enough current to operate the fan. A great mechanic in Nashville fixed for $80!
Thanks for keeping us posted!
I just went out to see what my Silverado would do. Once it idled down from cold start up. Neither fan was turning, I turned the AC on and both fans kicked in within 5-10 seconds of turning the AC on. Turned AC off and both eventually stopped spinning. So as I expected, turn on AC and both fans should operate.
You could always get a lower temperature thermostat if the high temperatures cause anxiety. A complete cooling system inspection and check is really the only way to see if there actually is a problem and correct it before you blow a head gasket. Then you're talking some real money.
Yeah I agree with @toyotagrl Both your cooling fans should turn on when you turn on the AC. Atleast initially..
I’ll conduct another test today using the proper working 08, run a side by side and see if the cooling fan issue continues. Will report back.
Conducted a side by side today, the 08 LT fans came on almost immediately. The 08 LTZ fans, only the drivers side fired up, still waiting on passenger side fan. The new question of the day - did the cheap Chinese fan die already or is the controlling module bad.
I ordered a TYC radiator fan assembly, does anyone know how to check the controller or module that activates the fans?
Would not surprise me that the cheap Chinese fan is dead. Do you have enough wiring slack to swap connections to at least check to see if the other fan is even operational?
No unfortunately not, and swapping the two out is a hour long process on each vehicle. I am definitely swapping the Ultra-power fan assembly out for the TYC tomorrow. I'll test it again. Will probably need to be something monitor, I imagine if the control unit is the problem it wont take long to figure out monitoring the OBDII.
More information -
Swapped the relay and the fan assembly, still not turning on. Checked the relay and replaced it, still no go. Also not getting any indication that there is power going through the fuse box. This probably has to go an experienced mechanic at this point.