Morris Minor Owners Club

So, the water round here is very hard, tap water tastes of limescale and kettles like to get excessively crispy so my question is, should I still flush out the radiator when changing the coolant using a hose pipe or skip that step to avoid the risk of adding limescale into the system or will it be unlikely to harm anything with the 50% coolant?

Thanks

Flush very very thoroughly with tap water regardless of hardness then drain it out. The limescale happens when the water is heated. My area is very hard water too. If you wish, you can de-scale the cooling system with a radiator flush you can buy or by adding citric acid to the coolant, running up to temperature, idling for 10 minutes or so then flushing it all out.

Stephen

Refill using distilled water or de-ironised instead of tap water

les wrote: ↑Sat Mar 09, 2024 6:28 pm Refill using distilled water or de-ironised instead of tap water

Yes! That is what I do and it makes a big difference. The coolant mixture stays pristine looking for a very long time.

You can even get distilled water for free if you have a condensing tumble dryer.

Stephen

Or just refill with premixed coolant after flushing.

les wrote: ↑Sat Mar 09, 2024 6:28 pm Refill using distilled water or de-ironised instead of tap water

Oh yes, I'd never use tap water, even when I lived in a soft water area.

Bill_qaz wrote: ↑Sat Mar 09, 2024 6:53 pm Or just refill with premixed coolant after flushing.

I already have the concentrate and deionised water purchased.

I live in the same hard water area, but would never countenance using anything but tap water for flushing and filling the cooling system. I suggest just working out how much calcium carbonate equivalent is involved. Put simply, it is simply not worth worrying about.