My trouble free 2007 Defender has never had the anti-freeze drained and flushed but probably had a litre added to keep it on the level mark on the header tank. The car has 30,000miles on the clock and is running on the original "OAT" red anti-freeze that can last for 100,000 or 10 years. I think a drain & flush can do no harm as it's currently showing protection on the glycometer of -10 only. There is no drain plug on the radiator and i was thinking of draining via the fuel cooler which is stupidly the lowest point?
Has anyone done this on a puma Defender and what is the best make of OAT?