Hi Kevin, I hope your daughter (and her car) made it home safe.

You got good advice, IMO.

From where you and I sit it's hard to tell the severity of the problem in your daughter's car. At risk of making assumptions about your daughter but isn't is a "fun" challenge to try to diagnose cars over the phone with someone who isn't quite so mechanically inclined? Gets me every time.

I'll add that I've limped along with a slight heater core leak for quite some time in a couple cars (thank goodness for that low coolant level indicator). Each car would go a few weeks between needing a top up and only display a strong coolant smell when the heat was on. No steamy windshield but a heavy haze that needed to be wiped clean after a couple months.

The third heater core leak I experienced was a failure at one of the O-rings that gushed fluid and caused overheating in the summer. That got fixed right away.

If it's not losing coolant too fast she is fastidious about keeping the level up, it may be OK until your next visit.

Best of luck,
Will