My rear heater coolant on and off valve located on the passenger side of the
heater unit under the back seat is leaking. It leaks at the on off spindle
that goes into the valve.

I need to know if the coolant will leak out when I replace this item. Since
I have learned how to bleed the system this should not be a problem for me
now, but is there a way to minimize any loss of coolant?

Is this a dealer only part? They want $45 for it part number 867 819 809.

Any advice?

William