Hi, I have seen coolant residue on the Heater Control Valve.
I will be replacing it, however, I have found Heater control valves that are used for other vehicles, but look exactly the same.
Will it cause any damage if the part designed for another brand of car is used in my car.
I assume that its job is to control the coolant in the cabin heater, so in my limited knowledge I don't think it will be an issue, but I

would like your views.

 

Coolant residue is most likely due to the hose leaking onto it and not the valve itself. Make sure the clamp is tight and/or replace the hose and clamp altogether.