Low coolant cause?

I was filling up my washers yesterday and while I was at it decided to check the levels of each compartment.

I noticed that my coolant is just above the low mark, when I first had the car it was above maximum but from what I understand that is normal as it expands when it gets warm.

Now my question is what would cause the coolant to get low? What will happen if it gets too low and is it worth taking it in to VW.

I'm going to be calling in there soon when I have some time and am in the area because my fuel flap is totally gone, I have to use something to force it open now but I know that is a simple fix.

It's a closed system so technically the coolant level isn't supposed to drop at all.

However, it can drop slightly just after picking up the car as everything's new and the engine is still settling in. It's important to check your levels, especially when the car is still new. Just to be on the safe side though (I actually had a coolant leak in my new Polo), check for leaks and/or white residue.

Take it back to the dealer if you feel something's wrong.