1997 850, 148,000 miles, manual climate controls. Recently started blowing a coolant fog out the vents, especially the middle ones. Get a lot more fog when the heater are in the warm zone.

Figuring it is heater core or a hose leak. Tried the easy route of putting cooling system sealer in; this may have slowed the leak but has not stopped it. Have driven about half dozen trips with the sealer in there (150 miles total).

Looked in Haynes manual, it was not much help finding how to get in there to find the leak.

Suggestions on where to start?

Thanks,

Terry