We have a thermal solar water heating system which pumps antifreeze round a boiler. Unfortunately it has started leaking at a rate of about one drip every couple of minutes. The liquid was soaking into our floor and starting to smell. As a temporary measure I have fashioned a tin foil funnel which channels the drips into a glass which you can see in the attached image. The drip appears to be emerging from the underside of the big nut you can see in the picture. It is very tempting to take a mole grip to that nut an see if tightening it will fix the problem but I am nervous that it could make things worse (I am not a plumber!). Am I right to be nervous or should I just go ahead and give it a go? I presume clockwise would be the way to turn the nut!?