Around town between 14 and 15 litres per 100 kms. On a trip dips below 10 if i go far enough.

Fwiw, only second rate media scribblers use the word 'guzzle' to describe a cars fuel economy. Its a pejorative term meant to shame drivers into going $30,000 into debt to save $20 a week.

A full coolant flush is unlikely to have much effect. Over the years ive had most things serviced, cleaned or replaced and fuel usage barely changes.