Originally Posted by cchrish0
hi just done that im now soaking wet (lol)but seems better should i see water coming back out through the water inlet. I only held it there for around 20secs.
Most likely you won't. The tube for the telltale is not large enough to supply a significant amount of water to the cooling system.
The telltale is not a functional system; it's more like the oil pressure idiot light on your car dashboard. It tells you that the system is working OK (if the telltale is working properly), but if it fails, it doesn't affect the rest of the system.