Coolant System Issues

[bimmerXfive]

I have just recently changed my expansion tank due to a split seam but now I cant get the hoses to seat properly and they all drip. They do seem loose when pushing them on. Does this mean the o-rings are shot and I need new hoses?

In the end I wound some teflon tape around the spigots on the expansion tank and then pushed the hoses on and it seems to work but I dont want to drive too far in-case my dodgey fix fails.

On another note what are the parameters for the coolant level sensor to come on? I believe that the sensor is a reed switch activated by a magnet on the float inside the tank? I have turned the ignition to on and held the float right down and no warnings come up. Does the car need to be running for the sensor to work and is there a test for it?

Cheers for your help.