Mostly short 3 mile journeys, lost 400ml of coolant in 8 months, never gone below the minimum any ideas,? 

Edited March 19, 20232 yr by Notabongo
Wrong amount

Have you been topping up to the max when the cars cold?

Topped up to in between min and max when cold the couple of times I've topped up.... I only do short mileage 2.5 mile commute every weekday.... Is 400ml over 8 months acceptable coolant loss with those short drives? 

Shouldn't be using any but I've noticed if I fill mine when cold it always seems to lose some till it finds its level just above the min mark. It never goes below min so I think it's pushing the extra out the over flow when hot. I've left mine months now and it's still at the same level.

I fill it cold to midway, never seen excess coming out of an overflow.... When it's hot the level is still about 35mm below the max level anyway.... I must check where the overflow is 

I had a slight coolant leak from the engine water pump. Similar levels lost, might be worth checking the pump.

Thanks Adam 

Ditto. It shouldn't be losing any coolant.

 

Assuming you don't have a head gasket leak (mayo on dipstick), I've found a leak detection dye useful in the past:

 

https://www.ringautomotive.com/en/product/RLD2

 

You can get a kit with a UV torch too.

Thinking of throwing little bottle of K seal in,