Everybody with mr freeze be carefull to put the fill plug back in properly. I just had a mishap in which I lost the fill plug because I accidentally locked it down wrong way. It shot out when the car was boosted, but luckily I check everything after every hard run. I never heard any detonation but it may have been disasterous if I hadn't seen that it was missing right away. I ordered two extra fill plugs and will make sure I never lock it down wrong again ! I'm going to attach the fill plug to a chain so it can't disappear if it happens to come out again (and so I can't lose it by dropping it). Hopefully it will never come out again. After talking with a guy from Anderson when ordering the new fill plug, he told me that the plug is adjustable. If you turn the lock down clockwise it is supposed to make it tighter.