My 3.8 Impala had a slight antifreeze smell from the engine compartment, and was much worse at the exhaust It was also missing, the problem was the upper intake plenum. I know that on this motor it is a common problem, and can quickly progress to the point of the car no longer running. You could have a small leak anywhere that is evaporating before it can drip.
An antifreeze leak.An antifreeze leak.
heater core leak
You have a coolant leak.
The smell of antifreeze is very strong and distinct, it does not take much of a leak to smell it. The radiator could still be full and have a small leak. I would check for antifreeze dripping onto the exhaust or on the engine block because when it is hot the smell is much more noticeable from the fumes.
You need to check for a leak.
A small amount of antifreeze smell may be emitted from the radiator overflow. However if you smell antifreeze you need to make sure there isn't a leak. It may be something simple if you catch it early.
if you smell it inside, it's the heater core it has a leak.
It probably has a leak, possibly from the heater core.
Your heater core has a leak, have the station pressure test your cooling system if it does not hold pressure you a leak in system
If you smell antifreeze, there must be a leak somewhere. Have the cooling system pressure tested.
If you're adding coolant to the reservoir often, you have a leak somewhere. Have the cooling system pressure tested. That may force the leak to show up.
Soundsw like heater core is going bad. You will smell antifreeze prior to actually noticing water/steam leak