Hello!

I have a 2008 Chevrolet Impala LS, 108860 miles, automatic transmission. In the past it has had issues with cooling itself, sometimes displaying an "Engine Hot A/C Off" warning, and having a low level of coolant in the recovery tank. I put coolant in by way of the tank and the warning had gone.

Now, several months later, I occasionally hear a sort of bubbling or gurgling sound from the area of the coolant recovery tank at various times whilst driving, but most reliably right after the car is shut off (this sound persists maybe two or three minutes). I could not see what was causing the sound exactly though, and there did not appear to be bubbling in the recovery tank when I checked it after stopping one time. I wondered if I had put air into the coolant system by mistake, but the coolant reserve was not empty  when I filled it. If you would be able to give your advice on that it would me much appreciated!

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If I may be so bold as to ask another question... I also have a 2007 Impala LT, automatic transmission, with 178870 miles. There comes a sort of rattling noise from the rear passenger-side area if pretty much anything changes abruptly (that is, moderately intense braking, or going over bumps). I thought it would be suspension, but there seem to be no tangible handling changes/difficulties.

Thank you so much, have a nice day!

-Travis