halfords anti freeze tester - how to use

GERMAN ROCKS

http://www.halfords.ie/webapp/wcs/stores/servlet/product_storeId_11101_catalogId_15551_productId_530559_langId_-1_categoryId_212616#tab4

i bought this anti freeze tester for the tractors but there is almost no instructions on how to use it.
So i took out the foam inside and an just wondering what way does the thermometer go inside the tube. at one part its a bit lager with tiny little balls and the other end is thinner. Which side should be where in the tube itself?
are these very accurate or is there a more concrete way to test. There is antifreeze in everything but just want to make sure its strong enough.

CiniO

You have to suck some of your coolant into that device, and you will see what's the freezing temperature of that coolant.

However in my experience those devices are very inaccurate.
They simply check the density of fluid. (as antifreeze has different density than water- so you can tell what's the proportion between water and antifreeze - so it's possible to tell the freezing temperature). If we are talking about pure antifreeze mixed with water, it will show precisely.
But coolant which was few years in vehicle, might contain many other substances (rust, oil, etc) and therefore it's density might be greatly affected, making this device showing rubbish.
I checked few days ago with similar device my friends coolant, and it showed freezing temp at about -30 degrees.
But to be sure we too a small bit into small bottle and put it into the freezer which is about -18 degrees. Coolant froze completely.

If you want precise reading, you need to get a device which is battery powered and can actually freeze a small sample of coolant. That way you will find out exact freezing temparature. Unfortunately those kind of devices are quite expensive.