09 3.5L v6 chevy malibu running hot. Radiator is new. Pressure test came back fine, so no leaks. Disappearing coolant that's never visible on the ground. My temp hand will rise just about to H in a matter of minutes. The car Never smokes, overheating light never comes on. Radiator fan will come on sometimes. The hand normally rises while driving and comes down when slowing down or stopping. My water pump is good. Coolant reservoir can be empty, then after driving it will magically be full to the top. My heat also blows out cool. When cranking, i can hear my coolant bubbling.My oil isn't milky so can't be a blown head gasket. And it doesn't smoke from the tailpipe. Any help would be great.
I've been having to keep adding coolant until recently. Now all of a sudden, the reservoir stays full after it filled itself back up.There is nothing milky in my oil or on the cap. My temp gauge would be almost on the H and the fan would never cut on. The fan Just start coming on at about the half way mark like 2 days ago. So, my reservoir would be completely empty after a few days. I would add more and the car wouldn't run hot unless the reservoir was empty. I've been having this problem since Nov (just getting worse) and I've only seen leaked coolant on the ground twice in the time from then to now. As of a few days ago, the coolant isn't disappearing out my reservoir anymore. But the car is still running hot in a matter of minutes despite the reservoir being full. So yes, the coolant has been disappearing but not visible. Therefore, it has to be going somewhere, but where right? I'll set an appointment with a shop so they can test and see if coolant is in the exhaust. But I haven't been smelling any.