If you've read my previous posts on cooling problems, you have seen what a bad cap can do to your system. Pressure is built up by the heating of your coolant, if you were to boil water with a pot and then try to hold a lid on it when it's hot, pressure will be built up and the lid will blow off (DON'T TRY IT, just get the idea!). The coolant gets to a certain point and stops before reaching a boiling point and blowing out the overflow-because it is being cooled it doesn't go to extreme pressure. Your bleeder works in a manner that it connects to a lower part in the system and forces the trapped air to mix with the coolant that is going ONLY back into the coolant tank (smaller diameter hose on the top)-which contains air 1-so the coolant can expand, and 2 since it is located highest in the whole system where it can't escape back into the system. Pressure in the tank helps push the coolant, no pressure and it will start to boil as your cylinders get hotter...after that things will warp and seize, those wonderful things. -----Dani B. #5003 --- In dmcnews@xxxxxxxxxxxxxxx, "sweetp01569" <paul.sweet@xxxx> wrote: > I am trying to understand the whole pressure situation with the > cooling system. Is it supposed to operate under pressure? The > previous owner of my car installed the self-bleeder arrangement. If > the bleeder continuously bleeds air, doesn't that mean the system > cannot pressurize if air/fluid is always "bleeding" from the system, > or am I not quite understanding how this system works? I also didn't > think the condition of my overflow bottle cap wasn't that important, > either, since I had the bleeder and that any overflow would simply > exit the overflow tube? What is the relationship between pressure, > the cap, bleeder arrangement and overflow tube from the bottle. I > don't see how they work together. > > Thanks, > > Paul > vin 10944 To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/