Today's engines are a bit different than they used to be. You're on the wrong forum to get good information on the specifics of that vehicle. If you don't even know if something is normal or not you need to ask people who are much more knowledgeable about it.
Oh yeah, here's something else: did you use the right antifreeze? You do know there are multiple kinds, right? They are all primarily ethylene glycol but the additives can be very different. Additives affect compatibility with internal metals and plastics the coolant is in contact with. I saw one vehicle which used THREE different kinds of coolant (it was a Toyota, and I know of some Mercedes vehicles which use two, although they are trying to standardize on Glysantin G40, which is the new coolant which is supposed to be more broadly compatible). Point being, you must use the proper coolant for your BMW, it really matters.
Peter
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On 9/15/2014 7:59 PM, edbreya@... [TekScopes] wrote:
Well, I put in a new tank and correct AF mix today and it seemed to work and hold pressure. Then I opened it up to check the coolant and it came gushing out again as before, so I thought the worst, that a head gasket leak was shoving it out from pressure buildup.
After stewing about it for a while and looking into repair options, it suddenly dawned on me that (I think) every time this happened was with the engine running, while it didn't do that when cool. The difference was that when cool, the thermostat was closed, limiting the loop flow to a civilized trickle, but when hot the flow was full, and the open cap was the path of least resistance to the water pump, so it ejected the coolant. Duhhh.
So fooling around with it less and checking with it shut down seems to show it's OK now - I hope. It also shows that simple things can be forgotten from not doing any serious car work for many years.
Ed
