coolant colour

[sivan]

Just had my bus serviced and mechanic says had a small coolant leak which he has repaired and topped up coolant ,but when I've looked in expansion tank coolant looks orange/rusty water colour, but still looks pink in header tank! Invoice says G12 coolant used, could there be a reaction of some type or has he topped up with wrong stuff ?

[R0B]

If in doubt drain and flush and fill again.