great thread, thanks for posting up Pete
i got home from the monthly NW meet last night to hear a strange noise (which i initially thought was someone scrambling around on the roof of the garage!) which turned out to be a large amount of bubbling going on in the expansion tank with the engine switched off :O
i daren't take the expansion tank cap off to see if it was just steam blowing through the water or the water actually boiling, but when it continued for about 10 mins i assumed it was steam blowing through
i left it to cool & when i came back to the car this morning, i found the expansion tank empty. i topped this back up to full & checked the rad cap, which came off with the little spring falling out at the same time. the water level appeared to be at the neck so i assumed this to be ok
so, my question is, should i be replacing the rad cap since the spring was not attached. a key factor i think is that my expansion tank is a small greddy replacement one that came with my front mount intercooler and the cap does not clip on very well, i.e. it could quite easily allow spits/dribbles of coolant out/steam as it was doing last night. as i'm typing this it already sounds really obvious that this needs sorting but i'm also unsure about the rad cap now i've read this thread
cheers,
wes