Anti Freeze

[chard]

I use the blue (2 year life stuff) Due to be replaced. Is it ok just to drain a couple of ltr's of coolant out and top up with antifreeze or should I drain flush and refill? The car only does a couple of thousand miles per year and I gave it a good flushing 2 yrs ago when I repalaced the water pump.

[paintman]

Drain & refill, then you know the concentration is correct.