2012 x6m overheating

[DR-2012 bmw x6 m]

hello. bough a 2012 x6 m series with 47k miles on it. my first bmw so Im just learnig bmw is not a "regular" car maker. it was crash when I got it so i have no history on it. So after I go thru the nightmare of buying parts for it (around 5k) still haven't driven it. it overheats. so far i replaced 3 of the electrical water pumps, thermostat, right now took everything apart again to make sure the mechanical pump was good, and of course it seems good. I see a small crack on the impeller on the small pump by the left inter-cooler but dont seem like it will cause the problem. so not sure if Im not bleeding the system correctly...( turn key for 11 seconds with brake on and let the pumps run) did that a few times....here is the unusual overheating...if I drive it very slowly,,not stepping on the gas,,it will not overheat..i could drive it for an hour and it will be fine...but if I drive it just around the block and step on the gas a couple of times...it will have coolant over floating all over..i can start it up and let it run on my driveway and still wont overheat, only when I step on the gas..please any advice will be appreciated....really want to take this for a ride,,,

[mirob]

Originally Posted by DR-2012 bmw x6 m

hello. bough a 2012 x6 m series with 47k miles on it. my first bmw so Im just learnig bmw is not a "regular" car maker. it was crash when I got it so i have no history on it. So after I go thru the nightmare of buying parts for it (around 5k) still haven't driven it. it overheats. so far i replaced 3 of the electrical water pumps, thermostat, right now took everything apart again to make sure the mechanical pump was good, and of course it seems good. I see a small crack on the impeller on the small pump by the left inter-cooler but dont seem like it will cause the problem. so not sure if Im not bleeding the system correctly...( turn key for 11 seconds with brake on and let the pumps run) did that a few times....here is the unusual overheating...if I drive it very slowly,,not stepping on the gas,,it will not overheat..i could drive it for an hour and it will be fine...but if I drive it just around the block and step on the gas a couple of times...it will have coolant over floating all over..i can start it up and let it run on my driveway and still wont overheat, only when I step on the gas..please any advice will be appreciated....really want to take this for a ride,,,

The S63 has a mechanical water pump, as you stated. You can't bleed the system like you would with an electrical pump. Unless, the auxiliary pump would perform that function...never had to do it so I don't know for sure, but I do know that the S63 doesn't have a bleeder screw so it's possible.

If I was you, I would cross post this on XBimmer forums, there is a lot more traffic over there, especially for the ///M.