Hey Folks, I'm new here just bought my 99 sunfire a few months ago not a bad car, but im having an issue im leaking coolant somewhere and i don't have any idea where i've only seen a spot in the driveway once and it only appears to be leaking when the car has been running for awhile. it doesnt leak anywhere when you first start the car, the exhaust doesnt smeel like anifreeze and when i turn my heat on i don't get the smell there either, i only smell it faintly when im looking around under the hood or underneatht the car, anyone else have a problem like this

 

try checking your heater core: a sweet smell in the interior with the defroster fan on; can cause windows to fog up; an oily film on the windshield; perhaps a leak out of the evaporator condensate drain or a slight mystery coolant loss.Always inspect the evaporator condensate drain located above the transmission bell housing.; Check the carpet on the passenger side for dampness.
check also other auto parts like the head gasket, intake manifold, oxygen sensor, etc.. observe and keep us posted of what other unusual thing did you notice. Good luck

 

check the coolant hoses or the pump for leaks (start the engine) or the hose to the heater

 

I would put my money on coolant pump. That starts to leak or seep at higher temperatures because of pressure building up inside the system. Just try to feel the liquid from the small hole under the pump when the engine is cold to touch. I am sure that you will see some wetness there and that is a good sign of pump leaking.

 

My Guess...

Waterpump or Head Gasket.

My wife has a 99 Sunfire with the 2.4 and we have had to replace both... it only has 107000K on it.

Apparently GM had a Service Bulletin on the headgasket and they were honouring repairs for up to 7 years/160000K I think it is.