Ok, so a few months ago I had annoying... serious cooling issues. Got a new thermostat and expansion tank... Wonderful
A week later I took my car to the shop after replacing all that and overheating again. Turns out there was a problem with my radiator cap... Alright. Fine. Got a new one. My mechanic got my old one to fit and work.. So I kept the other one as a spare
Well I took off my radiator cap to check my coolant this morning. It was low, and i noticed a broken O-ring on my old radiator cap. I went back inside and got the new one and put it on and drove to work.. When I put it back on, it felt like it jumped the threads...

.... so I fiddled with it until I got it on correctly... so I thought.
Sure enough, when I got to work and stopped my car... I had a lovley green puddle.
Today just keeps getting better and better. Does anyone have any strategies on how to get this thing to sit on there right? I'd love to fix the problem and spend more money (right....) on another new radiator cap and expansion tank. Unfortunatley my direct deposit doesn't come through until tonight and I'd like to make it home after work...