New to the the forum, hopefully someone can help me out here.

I have a 90 Jetta (automatic) with a history of heating up. The cooling system is almost brand new - new heater core, water pump, rad - but the temperature gauge still spikes, but only when it rains. It also starts to smell like antifreeze when the heat is on (only when it rains).

I've had to continually fill the coolant, so I have a bad feeling that it's the head gasget...although I haven't noticed it in the oil.

Thanks.

Is the floorboard around the airbox getting wet with coolant, like a leaking heater core? Do you get white smoke (steam) out of the exhaust even after the engine warms up?

No, not getting any steam or liquid from the heater core.