2008 Cobalt - Coolant Mystery
I'm helping my girlfriend flush the radiator on her her 2008 Cobalt LT before a long road trip vacation next week. The car just rolled 101,000 miles, and to my knowledge the radiator has not been flushed in the 4 years she has had the vehicle. Her engine is the 2.2L model.
I drained the old fluid and then filled the reservoir with distilled water and ran the car for about 15 minutes to cycle the water and flush everything out. After draining the distilled water, we checked the owner's manual and noticed that 7 quarts is the recommended coolant capacity. I bought some 50/50 solution and poured it in, but the car only took about 5 quarts, and the reservoir is overfilled above the "COLD FILL" line. I figured that when the air pockets were sucked out the reservoir level would drop and we would add more coolant, but that never happened.
Based on what I've read, you're supposed to run the car until the cooling fan kicks on and the air is sucked out of the line, then add coolant until you get to the correct level. The problem is that her cooling fan seems to always be on as soon as you start the car. I watched the temperature gauge and the normal running coolant temperature was 180-190 degrees Fahrenheit. By turning on the heater, I was able to bump it up to 203, but the excess coolant never filtered down. Her AC and heat work and the car is not overheating, but it seems strange to me that the coolant is overfilled at 5 quarts when the owners manual calls for 7?
Am I doing something wrong, or is this normal? I appreciate any advice you guys can offer. Thanks!