I HAVE A 1998 LEGACY OUTBACK NO SMOKE NO SWEET

Could be a couple of things. If it smells sweet you may have a leak in your heater core. If it smells burnt it may be you heater fan is worn out. Does your fan make abnormal sounds?

the smoke is probably coolant steam and the sweet smell is the unique aroma of engine coolant (anti-freeze). check the carpets, they may be wet with coolant. most likely a heater core failure.

Steam is not smoke. Smoke would be from oil burning, the steam would be overheated coolant which is 50% H2O. Oil making white smoke, more than a little would have a smell that irritates the eyes and nose
while the steam from overheated coolant will smell sweet. The mixing of coolant and oil will be apparent on the oil fill cap when major damage has occurred and looks like coffee with cream.

You need to smell the white smoke. If it is still burning coolant, the smoke will smell sweet and it will dissapate fairly quickly. if it stays like a cloud and doesn't have a sweet smell then it is most likley oil. When you changed the head gaskets did you check the heads for flatness? When you say it's not losing any coolant, how are you checking? do you take the cap off the radiator or do you look at the overflow tank? It doesn't take much coolant leaking into the cylinders to make white smoke. I would do a pressure test of the cooling system.

Your heater core has developed a leak (of coolant). The smell is the "sweet" smell of ethylene glycol,
a component of engine coolant. The white smoke is steam coming from the heated coolant evaporating.
The coolant is dripping into your duct work under the dashboard, and apparently being evaporated
out of the ductwork and sent into the passenger compartment, meaning its a small leak.
When the leak gets worse, you may get wet carpet on the front passenger side.

If it doesn't smell like sweet then you most likely got a bad tank of gas. Just to be safe keep an eye on your engine temp. and coolant levels.

this smell from tail pipe may be burning coolant, does it smell sweet, if so have head gasket checked. when a car has problems with something from tail pipe. it is usually the head gasket that is bad.

If it smells sweet it is coolant and this is a sure sign your heater core is leaking. The only fix is to replace it.

smell the exhaust first, if it is sweet smelling, it may be the headgasket.

Please check the radiator it may be leaking or there may be hole in the coolant container or the sensor is defective get it checked ..................................