My guess is that the smell is stoping because the small
amount of coolant leaking from the core or leaking from
a hose/seal is burning off. This advice coming from
experienced Volvo people not I. They say it will get worse
if origin of problem is not addressed.

The golden yellow color is what I'm talking about. New
Volvo coolant is dark green in the jug and florescent green
when mixed with 50/50 DI water. I'd like to know if it's normal
for Volvo coolant to change like this.

You may want to do cooalnt flush again and see if there is a
change in your heater core problem. Every two years won't hurt and may help.


rd