No sweet smell, slime, or drips. Also, I checked the coolant reservoir that has the min and the max lines and it was right in the middle of both this morning. Now if there was air in the system or a leak wouldn’t my car be overheating? And wouldn’t the noise persist for a little bit even after I turn the car off? From just looking on google when people have air in their coolant it seems like their cars overheat and the noise stays for a little bit even after they turn the car off. My temp gauge is right in the middle where it normally is and the sound stops as soon as I turn the key to off.