Thank you for your help!

I'm trying to trace a leak in the cars liquid cooling system. It only contains water (per now, but in the winter it should obviously contain antifreeze). Is there really a point in filtering it? The water quality doesn't really matter, for the sake of the argument I could fill it with Coke.

What about this flashlight?
http://www.dealextreme.com/details.dx/sku.4014