Heater Core Leak?

[Bav3.5]

Thoughts on this gunk on my heater core? This is a view looking up through the driver's floor vent. It is not wet (after a few recent drives), and in the 10 years i've owned the car, it has never really had issues losing coolant. I looked because I once or twice thought I smelled coolant with the heater on, but it was only for a few seconds if anything. Could this be some stop-a -leak product a prior owner poured in? Thanks.

Tim

 

[jefftepper]

My thinking is that you have had a slow leak for a long time and the stalagmites are forming.... Time for a new core.